Bava Metzia 4a, Heilach הילך

The sugya of Heileich is one of the most famous in Shas.

Equally famous is the difficult Rashi. The conventional understanding is the הילך means הי לך -here, says the borrower - presumably at hand - is the money that I owe you. But Rashi says the money is not at hand, it is elsewhere in the possession of the borrower, who never actually expended the money:

How can one say that the money still belongs to the lender? As the Gra notes, the Ran has a similar explanation, but only in regard to a pikadon, which does in fact belong to the mafkid wherever it is.

I believe that the explanation of Rashi can be found in the ראב"ן:

explained by the Even Leshem b'Dvir:

Clearly, the Ra'avan reflects Rashi's understanding. Even when it comes to a loan, the money has the status of a pikadon until actually expended!