Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates from Sayyiduna Abu Talhah (may Allah be pleased with him), who said: I came to the Messenger of Allah (peace and blessings be upon him) and the lines of his (peace and blessings be upon him) face were shining. I said: O Messenger of Allah! I have never seen you as cheerful and bright-faced as you are today. He (peace and blessings be upon him) said: "Why should I not be happy? Jibril (peace be upon him) has just now left me. He said: 'O Muhammad! Whoever of your Ummah sends blessings upon you once, Allah records ten good deeds for him, erases ten of his sins, and raises him ten degrees, and the angel says for him the same as he said for you.' I asked: 'O Jibril! What angel is that?' He said: 'Indeed, Allah, the Mighty and Majestic, has appointed an angel to you from the time of your creation until your being sent (as a Prophet); whoever of your Ummah sends blessings upon you, he says: And may Allah send blessings upon you too.'"
Hadith Referenceالمعجم الكبير للطبراني / باب الزاي / 4703