Sayyiduna Abu Razin al-Uqayli (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "O Abu Razin, when a Muslim goes to visit his Muslim brother, seventy thousand angels accompany him, praying for mercy for him and saying: 'O Allah, just as he kept ties with him for Your sake, so keep ties with him.'"
Imam al-Tabarani recorded it in al-Mu'jam al-Awsat. Its chain contains a narrator, Amr bin al-Hisn, and he is matruk (abandoned).