Sayyiduna Abu Hurayrah (may Allah be pleased with him) says: He (peace and blessings be upon him) went out to visit a man from among his Companions who had a fever, and I was with him (peace and blessings be upon him). He (peace and blessings be upon him) took hold of his hand and placed his own hand on his forehead, and he (peace and blessings be upon him) considered that part of the completeness of visiting the sick. Then he (peace and blessings be upon him) said: "Indeed Allah, the Blessed and Exalted, says: 'It is My fire which I set upon My believing servant, so that it becomes his share of the Fire in the Hereafter.'"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6591