Charles H. Spurgeon on Psalms 74:3

Lift up thy feet. Or, thy hammers, that is, "thy strokes, "to "stamp" or "beat down" the enemy "unto perpetual desolations." Thus the "feet" are used to "tread down with, " Isa 26:6; and so the Greek taketh it here, changing the metaphor, and translating it, "Thy hands, "which are also instruments to strike down with. Or, lift up thy feet, that is, come quickly to see the perpetual desolations, which the enemy hath made. Henry Ainsworth.