Ecclesiastes 12:2-3

Solomon likened the evil days first to an approaching rainstorm (Ecclesiastes 12:2) that is fearful and uncertain (cf. Ecclesiastes 11:7-8). The Hebrews regarded any decline in a person’s vital energy as a sign that death was beginning to set in (cf. 1 Kings 1:1-4; Psalms 18:4-5; Psalms 88:3-5).

The "watchmen of the house" (Ecclesiastes 12:3) probably refer to one’s arms and hands, and the "mighty men" to the legs. The "grinding ones" are probably the teeth, and "those who look through windows" the eyes.