Ecclesiastes 10:10; Ecclesiastes 12:3

Ecclesiastes 10:10

10 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.

Ecclesiastes 12:3

3 In the day when the keepers of the house shall tremble, and the strong men shall bow themselves, and the grinders cease because they are few, and those that look out of the windows be darkened,