"Allaah has promised to those amongst you who believe and do righteous actions that He will certainly grant them khilaafah (succession) on the earth, as He granted it to those before them; and that He will grant them authority to practice their religion, the one that He has chosen for them; and He will change their state from one of fear in which they lived to one of peace and security. They will worship Me alone, not associating any partner with Me. But whosoever disbelieves after this, then they are the rebellious ones." 
Al-Haafidh Ibn Kathir (d.774H) - rahimahullaah - said: [
"This is a promise from Allaah - the Most High - to His Messenger, may the prayers of Allaah and the peace be upon him, that He will make his Ummah the khulafaa’ (successors) upon the earth. Meaning that they will be the leaders and rulers over mankind, by which nations will be corrected and to whom mankind will submit. And that He will replace their state of fear in which they lived, to one of security and dominion. Allah - the Blessed, the Most High - has fulfilled His promise, and to Him belongs all praise and thanks. For the Prophet did not die until Allaah made him conquer Makkah, Khaybar, al-Bahrain, the remaining lands of the Arabian peninsula and the whole of Yemen. He took jizyah corn the magians of Hajar and from the people of the surrounding areas of Syria. The Prophet received gifts from Heraclius - the king of Rome; the ruler of Egypt and Alexandria - the Mawqawqis; the kings of Omaan; and Negus, the king of Ethiopia, who became king after Ashamah died - may Allaah have mercy upon him and grant him nobility.
After the Messenger of Allaah died, Allaah having chosen for him the reward which is with Him, Abu Bakr as-Siddiq was then established as his Khalifah (successor), taking charge unwaveringly. Abu Bakr took the Arabian peninsula and put it in order. He sent forth the armies of Islaam to the lands of Persia, under the command of Khaalid ibn al-Walid, . They conquered parts of these lands, slaying a number of its inhabitants. A second army was sent to the lands of Syria, under the leadership of Abu ’Ubaydah - - and those who followed him. A third aarmy was sent to Egypt under the leadership of ’Amr ibn al-’s . It was during his time that the armies sent to Syria conquered the cities of Busra, Damascus and its environs from the land of Hawraan and its surroundings. Allaah - the Mighty and Majestic - took Abu Bakr's soul - choosing for him the reward which is with Him. Allaah blessed the people of Islaam by inspiring as-Siddiq to choose ’Umar al-Faaruq as a successor.
’Umar then stood up, taking charge completely. The heavens will not witness - after the Prophets - anyone like ’Umar , whether in the strength of his reign or the fulfillment of justice. It was during his time that the conquest of Syria was completed; as was that of Egypt to its farthest reaches, as well as the province of Persia. He destroyed Kisraa (Chosroes) and humiliated him to the utmost, forcing him to retreat back to the furthest reaches of his kingdom.
Similarly, ’Umar destroyed Qaysar (Caesar), wresting from his hands the lands of Syria and bottling him up in Constantinople. He spent the wealth (conquered from them) in the path of Allaah - as the Messenger of Allaah had informed and promised - may the most complete salaam and most purest salaah be upon the Messenger from his Lord.
Then there was the rule of ’Uthmaan , under whom the possessions of Islaam extended to the furthest eastern and western reaches of the earth. The lands of the west were conquered to the farthest reaches of what lies there - Andalus, Cyprus, the lands of Qairawaan and the lands of Ceuta - which is next to the all-encompassing ocean; and to the farthest lands of China. Kisraa was killed and his kingdom totally vanquished. The cities of al-’Iraaq, Khurasaan and Ahwaaz were conquered and the Muslims slew a large number of Turks. Allaah having humiliated the Turks and their great king the Kha-Khan. The wealth of the east and the west was collected and brought to the Amirul-Mu’minin (leader of the Believers) ’Uthmaan ibn ’Affaan, . All this came about as a result of the blessings of his recitation, study and gathering the Ummah upon the preservation of the Qur'aan.
It is confirmed in the Saheeh  that the Messenger of Allaah said: "Indeed Allaah gathered up the earth for me, so that I saw its east and west. Indeed, the dominion of my Ummah will reach what gathered up for me, from it."
We fluctuate in what Allah has promised us with and in what His Messenger has promised. Allaah and His Messenger have spoken the truth. We ask Allaah to grant us Imaan (faith) in Him and His Messenger , and that we establish gratitude for what Allaah has given us, in the manner that He is pleased with.
Imaam Muslim ibn al-Hajjaaj said in his Saheeh, that Ibn Abi ’Umar related to us, that Sufyaan related to us from ’Abdul-Maiik ibn ’Umayr, from Jaabir ibn Samarah who said: I heard the Messenger of Allaah, say: “The affair of the people will continue to remain upright while twelve men are in charge of them.” The Prophet then said something which I could not make out. So I asked my father: What did the Messenger of Allaah, , say? He replied: “They are all from Quraish.” This narration is also reported by al-Bukhaaree. 
In this narration there exists a clear evidence that all twelve of these men must be leaders from Quraish. They are not the twelve imaams claimed by the Shi’ah, because many of them had no leadership over the Muslims. As for these twelve, they will be from Quraish and they will be just rulers. The glad tidings of their appearance has also occurred in the previous scriptures. Furthermore it is not necessary that they succeed one another. Rather, their appearance in the Ummah could be successive or separate. Four of them were in order, namely, Abu Bakr, ’Umar, ’Uthmaan and ’Ali, . After these four there was a gap. Others amongst the twelve appeared as and when Allaah willed. It is possible that some of them will appear during a time only which Allaah - the Most High - knows. Among them will be the Mahdi whose name will be that of the Messenger, , and his kunyaa that of his kunyaa. He will fill the earth with justice as it is filled with tyranny and injustice.
Imaam Ahmad, Abu Daawud, at-Tirmidhi and an-Nasaa’i have all reported from the hadeeth of Sa’id ibn Juhmaan, from Safinah - the mawlaa of the Messenger of Allaah , that the Messenger of Allah said: “The Succesorship (al-Khilaafah) after me will last for thirty years. Then kingship will appear.” 
Ar-Rabee’ ibn Anas has said that Abul-’liyah has remarked concerning this verse: “The Prophet, , and his Companions were in Makkah for ten years afraid, secretly calling to Allaah and His worship alone, He has no partner. They remained in such a state until they were ordered to migrate to Madeenah. They were ordered by Allaah to fight. While they were (in Madeenah) they were in constant fear (of attack). They would go to sleep armed and awake armed. They remained patient upon that state as long as Allaah willed. Until one day, one among the Companions said: “O Messenger of Allaah! Will we remain in a state of fear until the end of time? Will there not come a day when we will be in a state of security, so we may lay down our weapons?” The Messenger of Allaah, , then said: “Be patient for a while. For there will come a time when any man from you would sit in a large crowd unarmed.” Allaah sent down this verse and made His Prophet victorious over the Arabian Peninsula. The Prophet's Companions were now safe and could lay down their weapons. Allaah - the Most High - then took the soul of His Prophet,&nbbsp;, and the Muslims remained in such a state during the leadership of Abu Bakr, ’Umar and ’Uthmaan . Until the Muslims fell into what they fell into from discord. So fear entered their hearts and they took armies and guards for protection. For they had changed, so Allaah changed their state.”
One of the Salaf has remarked that the khilaafah of both Abu Bakr and ’Umar is true. He then recited this verse. Al-Bara’ ibn ’Azib has said: “This verse was revealed while we were in a state of extreme fear.”
This noble verse is similar in meaning to His statement - the Most High: “And remember when you were few and were reckoned weak in the land and were afraid that men might kidnap you, but He (i.e. Allaah) provided a safe place for you, and strengthened you with His help and provided you good things so that you might be grateful.” 
His statement - the Most High: “as he granted that to those before them.” This verse is similar to what Allaah has said about Musa, ’alayhis salaam, that he said to his people: “It may be that your Lord will destroy your enemy and make you succeed (the present rulers) on earth, so that He may see how you act.” 
And Allaah - the Most High - has said: “And We wished to confer a favor upon those who were oppressed in the land; and to make them leaders and to make them heirs; and to establish them on earth...” 
And Allaah's statement: “And that He will change their state after the fear in which they lived to one of security and peace.” This is similar to what the Messenger of Allaah , , said to ’Adi ibn Haatim when ’Adi came as a delegation to the Messenger . The Messenger said: “Do you know Hira?” ’Adi replied: “I have not seen it but I have heard of it.” The Messenger then said: “By Him in Whose Hand is my soul! Allaah will complete this matter (i.e. Islaam) until a woman will be able to travel from Hira until she goes around the House (i.e. the Ka’bah) not needing the protection of anyone. And you will certainly conquer the treasures of Kisra ibn Hurmuz.” I (i.e. ’Adi) replied: “Kisra ibn Hurmuz!” The Prophet replied: “Yes! Kisra ibn Hurmuz. Money will be spent until no-one will accept it.” Adi ibn Haatim said: “Now here is the woman leaving from Hira until she goes around the House. And I was among those who conquered the treasures of Kisra. And by Him in Whose Hand is my soul! The third matter will come to pass because the Messenger of Allaah , has said so.”
Ahmad reports upon ’Ubayy ibn Ka’b who said that the Messenger of Allaah, has said: “Give good news to this Ummah of ease of life, exalted stature, establishment of their religion, victory and leadership on earth. Whoever does acts of the Hereafter for this world, he will have no portion of the Hereafter.” 
And Allaah's statement: “They worship Me alone and do not associate anything with Me.” Ahmad reports upon Mu’aadh who said; I was sitting behind the Prophet , on a donkey. There was nothing between the Prophet , and I except the end of his saddle. The Prophet said to me: “O Mu’aadh ibn Jabal!” I said: “Here I am O Messenger of Allaah in your service.” The Prophet continued to ride on for some time and then he said to me: “O Mu’aadh ibn Jabal!” I said; “Here I am O Messenger of Allaah in your service.” The Prophet said: “Do you know what is the right of Allaah upon His slave?” I said: “Allaah and His Messenger know best.” He said: “The right of Allaah upon the slaves is that they worship Him and do not associate anything with Him.” The Prophet continued to ride on for some time and then he said to me: “O Mu’aadh ibn Jabal!” I said: “Here I am O Messenger of Allaah, at your service.” The Prophet said: “Do you know what is the right of the slaves upon Allaah if they (worship Him alone)?” I said: “Allaah and His Messenger know best.” He said: “The right of the slaves upon Allaah is that He does not punish whosoever does not associate anything with Him.” This narration is also reported in the two Saheehs. 
And Allaah's statement: “But whoever disbelieved after this, they are the rebellious ones.” Meaning: Whoever steps outside of my obedience after that promise, he has stepped outside of the Command of His Lord, and sufficient is that as a great sin. Since the Prophet's Companions, were the most upright and obedient of people after the Prophet, in fulfilling the Commands of Allaah - the Mighty and Majestic - their victory was accordingly. The Companions of the Prophet made the Word of Allaah supreme, so Allaah Himself aided hem in such a manner that He subdued for them the rest of mankind, as well as their lands.
When the people after the Prophet's Companions fell short in adhering to some of Allaah's Commands, their victory accordingly fell short. It is, however, affirmed in both Saheehs (i.e. al-Bukhaaree and Muslim) in many ways from the Messenger of Allaah that he said: “There will not cease to be a group from my Ummah victorious, upon the Truth, not being harmed by those who abandoned them or go against them, until Allaah's affair comes, and they are like that.” 
And in a narration: “Until the last of them fights Masihud-Dajaal.” 
And in a narration: “They will be victorious until the Day of Judgment, then ’Eesaa ibn Maryam will descend.” 
All these narrations are authentic and there is no contradiction between any of them.
Shaykh ’Abdur-Rahmaaan as-Sa’di (d.1376H) said:  “This is one of His true promises whose meaning and accomplishment has been witnessed. He promised those who came with imaan (faith) and ’amalus-saalih (righteous and correct actions) from this Ummah, that He will cause them to be the successors upon this earth, so that they are the ones in authority and in charge of the affairs. Further, that He would establish their Deen - that which He was pleased with for thhem, which is the Deen of Islaam, which gained ascendancy over all other religions. He was pleased with it for this Ummah, due to its excellence, nobility and His favors upon it, in that He enabled them to establish it, and to establish its laws and prescriptions - relating both to manifest and non-manifest matters - upon themselves and upon others, so that the people of other religions and the rest of the unbelievers are conquered and humbled.
And that He would change their condition of fear to one of security, since it was previously the case that one of them would not be able to manifest his Deen, and they suffered harm and injury from the unbelievers. The united body of Muslims was very small in number, in comparison to the rest of the people of the earth, who combined to attack them and hope for their downfall.
However, Allaah promised them these things when the aayah was sent down, at a time when they were not witnessing ascendancy and establishment upon the earth, nor the ability to fully establish the Deen of Islaam and full security - such as would enable them to worship Allaah, not associating anything with Him - in a state of not having to fear anyone except Allaah.
So the first and foremost ones of this Ummah combined imaan and righteous and correct action to a degree surpassing everyone else, so He established them in the land and gave them authority over the people, and granted them the conquest of the east and the west. They attained full security and complete authority and establishment - and this one of the astounding Signs of Allaah.
This applies until the Hour is established - that
whenever the Muslims combine imaan and righteous and correct action -then
that which Allaah promises will certainly occur. Indeed, Allaah only grants
that they be overcome by the unbelievers and the hypocrites, and that they
suffer humiliation when the Muslims neglect Imaan and righteous and correct