It is narrated from Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Do not give anything as an 'umra and do not make a ruqba. Whoever gives something to someone as an 'umra or a ruqba, it becomes inheritance."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الهبات / 11987