Silsilat al-Ahadith al-Sahihah

It is narrated Mursal from Ali bin Husayn that the Prophet Muhammad (peace be upon him) said: "When any of you has love for his brother for the sake of Allah Almighty, then he should make it clear to him, because this clarification improves affection and keeps love lasting."

Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates that a man passed by the Prophet (peace and blessings of Allah be upon him) while a group of people were sitting with him. One of the men sitting with the Prophet said about the man who passed by: "I love him for the sake of Allah." The Prophet (peace and blessings of Allah be upon him) asked: "Have you informed him?" He replied: "No." The Prophet (peace and blessings of Allah be upon him) said: "Go and inform him." So he went to him and informed him. The man replied: "May the One for whose sake you love me, love you in return." Then that man came to the Messenger of Allah (peace and blessings of Allah be upon him) and told him what he had said. The Prophet (peace and blessings of Allah be upon him) said: "You will be with the one whom you love, and you will receive the reward you hope for."