Abu Idris al-Khawlani (may Allah have mercy on him) said: I entered the mosque of Damascus and saw a young man with gleaming front teeth who kept long silences, and the people were with him; whenever they differed over something, they referred it to him and acted on his opinion. I asked about him and was told: This is Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him). The next day I went to the mosque early, and found that he had gone before me and was praying. So I waited until he completed his prayer, then came to him from in front and greeted him with salam, and said: By Allah, I love you for the sake of Allah. He said: Do you say it by Allah? I said: By Allah. He again said: By Allah? I said: By Allah. He again said: By Allah? I said: By Allah. The narrator said: Then he took hold of the knot of my cloak and pulled me towards him, and said: Rejoice, for I heard the Messenger of Allah (peace and blessings be upon him) say: Allah Almighty says: "My love is due to those who love one another for My sake, who sit together for My sake, who give to one another for My sake, and who visit one another for My sake."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17286