Ecclesiastes 10:8-11

He who digs a pit will fall into it, and a serpent will bite him who breaks through a wall. He who quarries stones is hurt by them, and he who splits logs is endangered by them. If the iron is blunt, and one does not sharpen the edge, he must use more strength, but wisdom helps one to succeed. If the serpent bites before it is charmed, there is no advantage to the charmer.