Ecclesiastes 10:8-11

⁸He that diggeth a pit shall fall into it; and whoso breaketh down a wall, a serpent shall bite him.

⁹Whoso removeth stones shall be hurt therewith, and he that cleaveth wood shall be endangered thereby.

¹⁰If the iron be blunt, and one do not whet the edge, then must he put forth more strength; but an advantage for giving success hath wisdom.

¹¹If a serpent bite before he is charmed, then there is no advantage to the charmer.