Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) said: The Ansar used to give things to the Muhajirun as lifelong grants ('umra). The Messenger of Allah (peace and blessings be upon him) said: "Keep hold of your wealth; do not give it as lifelong grants. Whoever is given something, it is his during his lifetime, and after his death it belongs to his heirs."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الهبات / 11974