Musnad Ahmad 307:7

Surayj narrated to us, he said: Abu Ma’shar narrated to us, from Ishaq ibn Ka’b ibn ‘Ujrah, from Abu Talhah al-Ansari, who said: The Messenger of Allah (peace and blessings of Allah be upon him) woke up one day in a good mood, and joy was seen on his face. They said: "O Messenger of Allah, you have woken up today in a good mood, and joy is seen on your face." He said: "Yes, a messenger came to me from my Lord, the Mighty and Majestic, and said: 'Whoever from your nation sends blessings upon you once, Allah will record for him ten good deeds because of it, erase from him ten evil deeds, raise him ten degrees, and return to him the like of it.'"