Silsilat al-Ahadith al-Sahihah

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates: The Messenger of Allah (peace and blessings be upon him) asked Sayyiduna Abu Dharr (may Allah be pleased with him): "Which link (i.e., good deed) of faith is the strongest?" He replied: Allah and His Messenger know best. The Prophet (peace and blessings be upon him) said: "To befriend for the sake of Allah, to have enmity for the sake of Allah, to love for the sake of Allah, and to dislike for the sake of Allah."