An ancient legend is told...
An ancient legend is told of a famous blacksmith who, having been arrested and chained in the castle's dungeon, began to examine the chains which securely bound him. He sought to discover a flaw in the links, a weakness in its strength, that might make it easier to break the chains.
His hope was dashed, for he recognized upon the chains the mark of his own craftsmanship. And it had been his boast that no one could break a chain which he had forged.
Thus it is with a sinner. One's own hands have forged the chain that binds, a chain that no human hand can break.