General Behavior (Kitab Al-Adab)
Dawud :: Book 41 : Hadith 5176
Narrated Imran ibn Husayn:
A man came to the Prophet (peace_be_upon_him) and said: Peace be upon you! He responded to his salutation. He then sat down. The Prophet (peace_be_upon_him) said: Ten. Another man came and said: Peace and Allah's mercy be upon you! He responded to his salutation when he sat down. He said: Twenty. Another man came and said: Peace and Allah's mercy and blessings be upon you! He responded to him and said when he sat down: and blessings be upon you! He responded to him and said when he sat down: Thirty.