Regarding the person who asks for permission to enter before he
gives the greeting, Abu Hurayra said, "He is not given permission until
he has first given the greeting."
'Ubayd ibn 'Umayr reported that Abu Musa al-Ash'ari asked permission
of 'Umar ibn al-Khattab, but he did not grant him permission. It seemed
that he was busy. Abu Musa came back and 'Umar had finished. He said, "Didn't
I hear the voice of 'Abdullah ibn Qays? Give him permission to enter."
He was told, "He has gone away," so he sent after him. Abu Musa said, "We
were commanded to behave like that (i.e. to go away after having asked
permission to enter three times)." 'Umar said, "Bring me a clear proof
of it." He then went to the gathering of the Ansar and questioned them.
They said, "Only the youngest of us will attest to that - Abu Sa'id
al-Khudri." He went with Abu Sa'id. 'Umar said, "Is something of what the
may Allah bless him and grant him peace,, may Allah bless him and grant
him peace, commanded hidden from me? Doing business in the markets distracted
me," i.e. going out to trade.
Abu Hurayra said, "When someone comes in and does not say, 'Peace
be upon you,' then say, 'No,' until he brings the key which is the greeting
(salam)."