Nedarim

A certain man had a son who used to carry off bundles of flax. Thereupon his father forbade his property to him.  'But,' said others to him, 'what if the son of your son is a scholar?'  He replied, 'Let him acquire it, and if my  grandson be a scholar, it shall be his.'  Now, what is the law? — The Pumbedithans  ruled, This is a case of 'Acquire, in order to give possession,' and such does not give a legal title. R. Nahman said: He [the son] acquires [it], for [the giving of] a sudarium too is a case of 'Acquire, in order to give possession.'  R. Ashi demurred: But in the case of a sudarium, who tells you that if he retains it, it is not his?  Moreover, the sudarium is a case of 'Acquire in order to give possession,' and 'Acquire [it] from now.'  But as for this property, — when shall he acquire it? When his grandson is a scholar: [but] by then the sudarium [whereby the transference was made] has been returned to its owner.  Raba [also] questioned R. Nahman: But the gift of Beth Horon was a case of 'Acquire, in order to give possession,' yet it was invalid? Sometimes he answered, Because his banquet proves his intention;  sometimes he answered, This is taught in accordance with R. Eliezer, who maintained that even the extra [given by the vendor to a customer] is forbidden to one who is interdicted by vow to benefit. We learnt, THE SAGES RULED, EVERY GIFT WHICH IS NOT [SO GIVEN] THAT IF HE [THE BENEFICIARY] CONSECRATES IT, IT IS CONSECRATED, IS NOT A GIFT [AT ALL]. Now, what does EVERY include? Surely it includes such as this case of stealing flax?  — No. It includes the case of the second version of Raba's ruling.