Ecclesiastes 10:8-15

He who digs a pit [for others] may fall into it, and a serpent may bite him who breaks through a [stone] wall. [Ps 57:6] He who quarries stones may be hurt with them, and he who splits logs may be endangered by them. [Prov 26:27] If the axe is dull and he does not sharpen its edge, then he must exert more strength; but wisdom [to sharpen the axe] helps him succeed [with less effort]. If the serpent bites before being charmed, then there is no profit for the charmer. The words of a wise man’s mouth are gracious and win him favor, but the lips of a fool consume him; the beginning of his talking is foolishness and the end of his talk is wicked madness. Yet the fool multiplies words, though no man knows what will happen, and who can tell him what will come after he is gone? The labor of a fool so wearies him [because he is ignorant] that he does not even know how to go to a city.