Abu Musa Ash'ari reported that he went to 'Umar bin Khattab and greeted him by saying: As-Salamu-'Alaikum, here is 'Abdullah bin Qais (RA) , 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 ( صلی اللہ علیہ وسلم ) 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): If he (Abu Musa) finds a witness he should meet him by the side of the pulpit in the evening and if 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 bin Ka'b), what does he (Abu Musa) say? Thereupon he said: Ibn Khattab, I heard Allah's Messenger ( صلی اللہ علیہ وسلم ) as saying so. Do not prove to be a hard (task-master) for the Companions of Allah's Messenger ( صلی اللہ علیہ وسلم ) , 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).

This hadith has been narrated on the authority of Talha bin Yahya with the same chain of transmitters but with this variation of wording: He (Hadrat 'Umar) said: Abu Mundhir (the Kunya of Ubayy bin Ka'b), did you hear this from Allah's Messenger ( صلی اللہ علیہ وسلم ) ? Thereupon he said: Yes. and he further said: Ibn Khattab, do not be a torment for the Companions of Allah's Messenger (may peace he upon him). No mention has, however, been made of the words of 'Umar (RA): "Hallowed be Allah" and what follows subsequently.