It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "When one of you wishes to give his land to his brother, let him give it to him as a free gift or give it to him to cultivate, and let him not give it for a third or a quarter (of the produce)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11254