Mac Problem....

Today' morning gathering was talking about the mac problem. In the play Jacob lent his mac to Peter. Because Peter mac wasn't there yet but he need to finish the homework for Mr. Carpenter. Jacob said "You need to return the mac to me before 5' O clock and with no damages, if there's any damages your new mac will be mine (The old mac will be Jacob's too)." Even that Peter know there's the possibility to drop Jacob's mac. But he still agreed. Then Peter used Jacob mac to do his homework. After he finish his homework he accidentally dropped Jacob's mac and the files were gone. So Jacob said "Your new mac will be mine (And the one that Peter dropped will be his)." Peter said "No. I can fix it. And the new mac will still be mine." The question is "Should Peter give his new mac to Jacob? Why?"

I think Peter should give his new mac to Jacob. Because promise is a promise. Even that is was a verbal agreement. If Peter break the promise, no one else will lend him their computer or other thing.