Abu Musa Al-Ash`ari has narrated that the Prophet (PBUH) said:

“You can never be (true) believers until you show mercy to one another.”

The Companions said, “We all show mercy, O’ Messenger of Allah.”

The Prophet replied,

“It is not the compassion that any one of you shows to his friend. It is the compassion and mercy that you show the people in general [that I mean].” (Al-Tirmidhi)