اَلسَّلَامُ عَلَيْكُمْ وَرَحْمَةُ اللَّهِ وَبَرَكَاتُهُ

As-salaamu 'alaykum wara'hmatullaahi wa barakaatuh

Peace be upon you, and the Mercy of Allah and His Blessings. A man came to the Prophet (ﷺ) and said: As-salaamu 'alaykum! He responded to his salutation. He then sat down. The Prophet (ﷺ) said: Ten. Another man came and said: As-salaamu 'alaykum wara'hmatullaah! He responded to his salutation when he sat down. He said: Twenty. Another man came and said: As-salaamu 'alaykum wara'hmatullaahi wa barakaatuh! He responded to him and said when he sat down: Thirty.

Reference: Sahih. Abu Dawud: 5195