In the Holy Qur'an

Repel (evil) with what is best, and lo! He between whom and you was enmity would be as if he were a warm friend (41:34)

In the Traditions

The Prophet said, "I have been sent to perfect the nobility of your character."

The Prophet said, "Good character melts sins as the sun melts ice, and bad character spoils an action just as vinegar spoils honey."

A man came to the Prophet saying "O Prophet of God, which prople have the most perfect faith?" "Those of them who have the best character", he replied.

Imam Ali said, "Cheerfulness is the basis of love, tolerance the burial of faults, conciliation the concealing of shortcomings, and there is no better relative than good character."