It is narrated from Sayyiduna Ka'b bin Malik al-Ansari (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever visits a sick person plunges into the divine mercy, and if he sits with him, he becomes thoroughly immersed in it (the mercy)."
This hadith is narrated from Sayyiduna Ka'b (may Allah be pleased with him) only with this chain.
Hadith Referenceالمعجم الأوسط / باب الألف / 903
Hadith Takhrij«أخرجه أحمد فى «مسنده» برقم: 16039، والطبراني فى «الكبير» برقم: 204»