Musnad Ahmad 962:172

'Ali ibn Ishaq narrated to us, 'Abdullah—meaning Ibn al-Mubarak—informed us, Yahya ibn Ayyub informed us, from 'Ubaydullah ibn Zahr, from 'Ali ibn Yazid, from al-Qasim, from Abu Umamah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The visitor of the sick wades into mercy." And the Messenger of Allah (peace and blessings of Allah be upon him) placed his hand on his hip, then said: "Like this, coming and going. And when he sits with him, mercy engulfs him."