Al-Matalib al-'Aliyah 971 — The best charity

It is narrated from Sayyidah Umm Kulthum bint Uqbah bin Abi Mu'ayt (may Allah be pleased with her) that she heard the Messenger of Allah (peace and blessings be upon him) saying: "The best charity is that given to a relative who hides enmity in his heart."
According to the imams of language and the commentators, 'kashih' is an enemy who keeps his hostility hidden within his breast or side (kashh); this deed has been declared the best because it involves complete opposition to one's own self and that highest degree of good conduct even towards a hostile relative which removes mutual resentments and paves the way for upholding the ties of kinship.