Rib'i ibn Hirash reported that a man of the Banu 'Amir came to
the Prophet, may Allah bless him and grant him peace, and said, "Can I
come in?" The Prophet, may Allah bless him and grant him peace, told his
slavegirl, "Go out and say to him,, 'Say, "Peace be upon you. Can I come
in?" He is not good at asking permission to enter." The man said, "I heard
that before the slavegirl came out to me and I said, 'Peace be upon you.
Can I come in?' Then the Prophet said, 'And on you. Enter!'"