Narrated Ibn `Abbas
The Prophet (ﷺ) said, "The one who takes back his gift is like a dog swallowing its own vomit, and we (believers) should not act according to this bad example."
Narrated Jabir bin `Abdullah
The Prophet (ﷺ) has decreed that preemption is valid in all cases where the real estate concerned has not been divided, but if the boundaries are established and the ways are made, then there is no preemption. A man said, "Preemption is only for the neighbor," and then he makes invalid what he has confirmed. He said, "If someone wants to buy a house and being afraid that the neighbor (of the house) may buy it through preemption, he buys one share out of one hundred shares of the house and then buys the rest of the house, then the neighbor can only have the right of preemption for the first share but not for the rest of the house; and the buyer may play such a trick in this case."
Narrated 'Amr bin Ash-Sharid
Al-Miswar bin Makhrama came and put his hand on my shoulder and I accompanied him to Sa'd. Abu Rafi' said to Al-Miswar, "Won't you order this (i.e. Sa'd) to buy my house which is in my yard?" Sa'd said, "I will not offer more than four hundred in installments over a fixed period." Abu Rafi said, "I was offered five hundred cash but I refused. Had I not heard the Prophet (ﷺ) saying, 'A neighbor is more entitled to receive the care of his neighbor,' I would not have sold it to you." The narrator said, to Sufyan: Ma'mar did not say so. Sufyan said, "But he did say so to me." Some people said, "If someone wants to sell a house and deprived somebody of the right of preemption, he has the right to play a trick to render the preemption invalid. And that is by giving the house to the buyer as a present and marking its boundaries and giving it to him. The buyer then gives the seller one-thousand Dirham as compensation in which case the preemptor loses his right of preemption."
Narrated 'Amr bin Ash-Sharid
Abu Rafi' said that Sa'd offered him four hundred Mithqal of gold for a house. Abu Rafi ' said, "If I had not heard Allah's Messenger (ﷺ) saying, 'A neighbor has more right to be taken care of by his neighbor,' then I would not have given it to you." Some people said, "If one has bought a portion of a house and wants to cancel the right of preemption, he may give it as a present to his little son and he will not be obliged to take an oath."