Yevamot 36B

ואמר ריש לקיש ⁠— לעולם לא קנה עד שיאמר ״פלוני ופלוני ירשו שדה פלונית ופלונית שנתתים להם במתנה וירשום״.

Reish Lakish and R' Yoḥanan dispute whether one must state that the receipt of the portions should be considered as a gift with regard to each recipient, or whether stating it with regard to one of them is enough to indicate that it is true for all. And Reish Lakish said: The inheritors will only ever acquire the portions as defined by the owner of the possessions once he says: So-and-so and so-and-so should inherit such and such a field and such and such a field that I have given to them as a gift, and they should inherit them, i.e., he must state explicitly for each recipient that their receipt of the portions should be considered a gift. Rava ruled that in this dispute as well, the halakha is in accordance with Reish Lakish.

ואידך, דתנן: הכותב כל נכסיו לבנו לאחר מותו, האב אינו יכול למכור ⁠— מפני שנתנן לבן, והבן אינו יכול למכור ⁠— מפני שהן ברשות האב. מכר האב ⁠— מכורין עד שימות הוא, מכר הבן ⁠— אין ללוקח כלום עד שימות האב.

And the other dispute concerns that which we learned in a Mishnah: In the case of one who writes a bill transferring ownership of all of his possessions to his son stating that the transfer should take effect immediately so that the son should gain the rights to use the possessions after his death, then although the father retained for himself the right to use the possessions until his death, he is unable to sell the possessions due to the fact that he gave them to the son, and the son is unable to sell the possessions due to the fact that they are still in the father’s possession. If the father sold the possessions, then they are sold to the extent that the purchaser may use them until the father dies. If the son sold the possessions during his father’s lifetime, the purchaser does not receive any rights to use the possessions until the father dies.