Reference for Bava Metzia 162:13

אפילו תימא רבי אליעזר ולא קשיא כאן שמשכנו בשעת הלואתו כאן שמשכנו שלא בשעת הלואתו

The scholars propounded: What if he simply said, 'Put it down'? — Come and hear: [IF HE REQUESTS,] 'KEEP [THIS] FOR ME' AND HE REPLIES, 'PUT IT DOWN BEFORE ME,' HE IS AN UNPAID BAILEE. From which it follows that if he does not particularise at all there is no obligation at all. On the contrary, since R. Huna said: If he replied. 'Put it down before you' — it is [only] then that he is neither an unpaid nor a paid bailee; it follows that if he does not particularise he is a paid bailee. But no conclusions are to be drawn from this.

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