Narrated Ibn 'Umar:
Allah's Apostle said: Islam is based on (the following) five (principles):
1. To testify that none has the right to be worshipped but Allah and Muhammad is Allah's Apostle.
2. To offer the (compulsory congregational) prayers dutifully and perfectly.
3. To pay Zakat (i.e. obligatory charity) .
4. To perform Hajj. (i.e. Pilgrimage to Mecca)
5. To observe fast during the month of Ramadan.
Book 19, Number 4546:
Narrated Abdullah ibn Amr ibn al-'As:
It has been narrated on the authority of AbdurRahman ibn Abdu Rabb al-Ka'ba who said: I entered the mosque when Abdullah ibn Amr ibn al-'As was sitting in the shade of the Ka'bah and the people had gathered around him. I betook myself to them and sat near him.
(Now) Abdullah said: I accompanied the Messenger of Allah (peace_be_upon_him) on a journey. We halted at a place. Some of us began to erect their tents, others began to compete with one another in shooting, and others began to graze their beasts, when an announcer of the Messenger of Allah (peace_be_upon_him) announced that the people should gather together for prayer. So we gathered around the Messenger of Allah (peace_be_upon_him).
He said: It was the duty of every Prophet that has gone before me to guide his followers to what he knew was good for them and warn them against what he knew was bad for them. However, this Ummah of yours has its days of peace and (security) at the beginning of its career, and in the last phase of its existence it will be afflicted with trials and with things disagreeable to you.
(In this phase of the Ummah), there will be tremendous trials, one after the other, each making the previous one dwindle into insignificance. When they are afflicted with a trial, the believer will say: This is going to bring about my destruction. When (the trial) is over, they will be afflicted with another trial and the believer will say: This surely is going to be my end.
Whoever wishes to be delivered from the Fire and enter the Garden should die with faith in Allah and the Last Day and should treat the people as he wishes to be treated by them. He who swears allegiance to a Caliph should give him the pledge of his hand and the sincerity of his heart (i.e. submit to him both outwardly as well as inwardly). He should obey him to the best of his capacity. If another man comes forward (as a claimant to Caliphate), disputing his authority, they (the Muslims) should behead the latter.
The narrator says: I came close to him (Abdullah ibn Amr ibn al-'As) and said to him: Can you say on oath that you heard it from the Messenger of Allah (peace_be_upon_him)? He pointed with his hands to his ears and his heart and said: My ears heard it and my mind retained it. I said to him: This cousin of yours, Mu'awiyah, orders us to consume our wealth unjustly among ourselves and to kill one another, while Allah says: "O ye who believe, do not consume your wealth among yourselves unjustly, unless it be trade based on mutual agreement, and do not kill yourselves. Verily, God is Merciful to you" (iv.29). The narrator says that (on hearing this) Abdullah ibn Amr ibn al-'As kept quiet for a while and then said: Obey him in so far as he is obedient to God; and disobey him in matters involving disobedience to God.
Narrated Alqamah ibn Wa'il al-Hadrami:
It has been narrated on the authority of Alqamah ibn Wa'il al-Hadrami who learnt the tradition from his father. The latter said: Salamah ibn Yazid al-Ju'afi asked the Messenger of Allah (peace_be_upon_him): Prophet of Allah, what do you think if we have rulers who rule over us and demand that we discharge our obligations towards them, but they (themselves) do not discharge their own responsibilities towards us? What do you order us to do? The Messenger of Allah (peace_be_upon_him) avoided giving any answer. Salamah asked him again. He (again) avoided giving any answer. Then he asked again--it was the second time or the third time-- when Ash'ath ibn Qays (find that the Holy Prophet was being unnecessarily pressed for answer) pulled him aside and said: Listen to them and obey them, for on them will be their burden and on you will be your burden.
Narrated Hudhayfah ibn al-Yaman:
People used to ask the Messenger of Allah (peace_be_upon_him) about the good times, but I used to ask him about the bad times fearing lest they should overtake me. I said: Messenger of Allah, we were in the midst of ignorance and evil, and then God brought us this good (time through Islam). Is there any bad time after this good one? He said: Yes. I asked: Will there be a good time again after that bad time? He said: Yes, but in it will be a hidden evil. I asked: What will be the evil hidden therein? He said: (That time will witness the rise of) the people who will adopt ways other than mine and seek guidance other than mine. You will know good points as well as bad points. I asked: Will there be a bad time after this good one? He said: Yes. (A time will come) when there will be people standing and inviting at the gates of Hell. Whoever responds to their call will be thrown into the fire. I said: Messenger of Allah, describe them to us. He said: All right. They will be a people having the same complexion as ours and speaking our language. I said: Messenger of Allah, what do you suggest if I happen to live at that time? He said: You should stay with the main body of the Muslims and their leader. I said: If they have no (such thing as the) main body and have no leader? He said: Separate yourself from all these factions, though you may have to eat the roots of trees (in a jungle) until death comes to you when you are in this state.