Sahih Muslim 2153 d

We were in the company of Ubayy b. Ka'b that Abu Musa Ash'ari came there in a state of anger. He stood (before us) and said: I ask you to bear witness in the name of Allah whether anyone amongst you heard Allah's Messenger (ﷺ) as saying: Permission (for entering the house) should be sought three times and if permission is granted to you (then get in). otherwise go back. Ubayy b. Ka'b said: What is the iiiatter? He said: I sought permission yesterday from 'Umar b. Khattab three times but he did not permit me, so I came back; then I went to him today and visited him and informed him that I had come to him yesterday and greeted him thrice, then came back, whereupon he said: Yes, we did hear you but be were at that time busy, but why did you not seek permission (further and you must have never gone back until you were permitted to do so). He said: I sought permission (in the manner) that I heard Allah's Messenger (ﷺ) having said (in connection 'With the seeking of permission for entering the house of a stranger). Thereupon he (Hadrat Umar) said: By Allah, I shall torture your back and your stomach unless you bring one who may bear witness to what you state. 'Ubayy b. Ka'b said: By Allah, none should stand with you (to bear testimony) but the youngest amongst us. And he therefore, said to Abu Sa'id: Stand up. So I stood up until I came to Umar and said: I heard Allah's Messenger (ﷺ) say this.

As-Salamu-'Alaikum, here is 'Abdullah b. Qais, but he did not permit him (to get in). He (Abu Musa Ash'ari) again greeted him with as-Salamu-'Alaikum and said: Here is Abu Musa, but he (Hadrat 'Umar) did not permit him (to get in). He again said: As-Salam-u-'Alaikum, (and said) here is Ash'ari, (then receiving no response he came back). He (Hadrat 'Umar) said: Bring him back to me, bring him back to me So he went there (in the presence of Hadrat 'Umar) and he said to him: Abu Musa, what made you go back, while we were busy in some work? He said: I heard Allah's Messenger (ﷺ) as saying: Permission should be sought thrice. And if you are permitted, (then get in), otherwise go back. He said: Bring witness to this fact, otherwise I shall do this and that, i. e. I shall punish you. Abu Musa went away and 'Umar said to him (on his departure): It he (Abu Musa) finds a witness he should meet him by the side of the pulpit in the evening and it he does not find a witness you would not find him there. When it was evening he (Hadrat 'Umar) found him (Abu Musa) there. He (Hadrat 'Umar) said: Abu Musa, have you been able to find a witness to what you have said? He said: Yes. Here is Ubayy bin Ka'b, whereupon he (Hadrat 'Umar) said: Yes, he is an authentic (witness). He (Hadrat 'Umar) said: Abu Tufail (the kunya of Ubayy b. Ka'b), what does he (Abu Musa say? Thereupon he said: Ibn Khattab, I heard Allah's Messenger (ﷺ) as saying so. Do not prove to be a hard (task-master) for the Companions of Allah's Messenger (ﷺ), whereupon he Hadrat 'Umar said: Hallowed be Allah. I had heard something (in this connection), but I wished it to be established (as an undeniable fact).

Malik related to me from a reliable source of his from Bukayr ibn Abdullah ibn al-Ashajj from Basr ibn Said from Abu Said al-Khudri that Abu Musa al-Ashari said, "The Messenger of Allah, (ﷺ), said, 'One asks permission three times. If you are given permission, then enter. If not, go away.' "

"Abu Musa sought permission to enter upon 'Umar. He said: 'As-Salamu 'Alaykum (Peace be upon you). May I enter?' 'Umar said: 'Once.' Then he was silent for some time. Then he said: 'As-Salamu 'Alaykum (Peace be upon you). May I enter?' 'Umar said: Twice.' Then he was silent for some time. Then he said: 'As-salamu 'Alaykum (Peace be upon you). May I enter?' 'Umar said: 'Three times.' Then he (Abu Musa) left. 'Umar said to the gate-keeper: 'What did he do?' He replied: 'He left." He said: 'Bring him to me.' So when he came, 'Umar said to him: 'What is this that you have done?' He said: 'The Sunnah.' He said: 'The Sunnah? By Allah! You had better bring me proof or a witness to clarify this, or I will do this or that to you.'" He said "So he came to us while we were sitting with Ansar. He said: 'O People of the Ansar! Are you not the most knowledgeable people about the Ahadith of the Messenger of Allah (ﷺ)? Did the Messenger of Allah (ﷺ) not say: "Seeking permission is to be done three time. Either you are permitted, or other wise leave?" The people began joking. Abu Sa'eed said: "Then I raised my head toward him and said: "Whatever punishment you are afflicted with because of this, then I shall be your partner in it." So he went to 'Umar to inform him him about it, and 'Umar said: "I did not know about about this."

that Uman bin Al-Khattab said: "I sought permission (to enter) from the Messenger of Allah (ﷺ) three times, then he permitted me."

The Messenger of Allah (ﷺ) said, "Permission is to be sought thrice. If permission is granted, you may enter; otherwise, go back." <b>[Al- Bukhari and Muslim]</b>.