A man came to the Prophet ﷺ and said, "Peace be upon you."The Prophet ﷺ returned his greeting, and after the man sat down, he said, "Ten."Then another man came and said, "Peace be upon you and the mercy of Allah."The Prophet ﷺ returned his greeting, and after the man sat down, he said, "Twenty."Then another came and said, "Peace be upon you and the mercy of Allah and His blessings."The Prophet ﷺ returned his greeting, and after the man sat down, he said, "Thirty."
حدثنا محمد بن كثير أخو سليمان بن كثير حدثنا جعفر بن سليمان عن عوف عن أبي رجاء العطاردي
أن رجلا جاء إلى النبي ﷺ فقال السلام عليكم فرد عليه ثم جلس فقال عشر ثم جاء آخر فقال السلام عليكم ورحمة الله فرد عليه ثم جلس فقال عشرون ثم جاء آخر فقال السلام عليكم ورحمة الله وبركاته فرد عليه ثم جلس فقال ثلاثون
Its isnad is sahih. The hadith was narrated by Abu Dawud 4/350, no. 5195, in the chapter on manners, on greetings, and Tirmidhi 5/51, no. 2689, who said, sahih hasan gharib, in the chapter on seeking permission, on what is mentioned regarding the merit of greetings, and Darimi similarly 2/360, no. 2640.