Hasan Basri (Radhiyallaaho Anho) was told that a particular person was backbiting about him. He sent a gift of dates to that person and said to him

 Hazhrat Abu Ummama Bahli (Radhiyallaaho Anho) said:

 “Someone would be shown his deeds on the Day of Judgment and he will see the good deeds which he hadn’t done. He would ask Allah Ta’ala

‘O Allah, where did these good deeds come from?’

Allah Ta’ala would say

‘These good deeds are because of those people who used to backbite about you and you didn’t know about them.’

WHAT IS BACKBITING?

The Prophet (Sallalahu allahi wassallam) once asked

“Do you know what backbiting is?”

The Sahabah (Radiyalla anhum) replied

“Only Allah and his Messenger know best”.

The Prophet (Sallalahu allahi wassallam) said

“Backbiting is when you say something about your brother that he wouldn’t like.”

The Prophet (Sallalahu Alahi wassallam) was asked

“If my brother is really like the way I talk about him, then is it also backbiting?”

He replied

“If what you say about him is true, then this is what Backbiting is. And if what you say about him is not true then that is imputation.”

Note: The above is a translation from another language. So, just remember that these are not the exact words.