Abd al-Rahman bin Abdullah said: Abu Bakr bin Amr bin Hazm (may Allah have mercy on him) came to Umar bin al-Hakam bin Thawban (may Allah have mercy on him) and said to him: O Abu Hafs, narrate to us a hadith from the Messenger of Allah (peace and blessings be upon him) in which there is no disagreement. So he narrated from Sayyiduna Ka'b bin Ujrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever visits a sick person wades into mercy, and when he sits with him, he seeks intercession within that mercy." The narrator said: He used to say to his companions: Let us also seek intercession, if Allah wills.
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16402