Majma al-Zawaid — Hadith 3770

Sayyiduna Amr bin Hazm (may Allah be pleased with him) narrates: I heard the Prophet (peace and blessings be upon him) say: "Whoever visits a sick person remains continually in mercy, until, when he sits with the sick person, he seeks intercession therein; and when he gets up from him, he remains continually immersed in mercy until he returns to the place from which he had set out."
Tabarani recorded it in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat, and its narrators have been declared trustworthy (muwaththaqun).