
If
a custodian intended to misappropriate a deposit, making a declaration
in front of two witnesses, from that moment he is liable for any mishap
that might befall it – so say Beit Shammai, but Beit Hillel say that he
is not liable until he acts, because of "...
if he did not lay his hand upon the goods..."
By
Rabbinical law, when someone pays money for a movable object, he does
not acquire it yet, and either party may renege. To finalize the sale,
the buyer must take possession, by lifting the object or drawing it to
himself. When gold is exchanged for silver, gold is considered
merchandise whose transfer completes the sale.