Silsilah as-Sahihah 2601 — How to seek permission

Kaladah bin Hanbal says: Safwan bin Umayyah sent me to the Prophet Muhammad (peace be upon him) with milk, colostrum, and small cucumbers. The Prophet (peace be upon him) was in the upper part of the valley. I went to him without greeting him or seeking permission. The Prophet (peace be upon him) said: "Go back and (first) say: As-salamu alaikum, may I come in?"