Ecclesiastes 10:8-11

He that diggeth a pit shall fall into it; and whoso breaketh an hedge, a serpent shall bite him. Whoso removeth stones shall be hurt therewith; and he that cleaveth wood shall be endangered thereby. If the iron be blunt, and he do not whet the edge, then must he put to more strength: but wisdom is profitable to direct. Surely the serpent will bite without enchantment; and a babbler is no better.