It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that a man mentioned to him (peace and blessings be upon him) the hardness of his heart, so he (peace and blessings be upon him) said: "If you wish to soften your heart, feed the poor and pat the head of the orphan."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 7094