The Jews used iron for axheads at a very early date. An axhead in those days was no more secure than it is in modern times, for the legislation of Moses deals with cases in which an axhead slips from the wood while a man is felling a tree (Deut. 19:5).
It was borrowed.
This was a spontaneous cry from the lad who was cutting the wood. There was probably no intention of appealing to the prophet for divine aid in recovering the ax. It was an outcry from a conscientious young man who had had the misfortune of losing something that had been borrowed and who in all probability was too poor to make good the loss.