The Hebrew amtsah is a feminine noun meaning strength, force, or might, derived from the verb amats (H553, to be strong). It appears in 2 Samuel 22:33 in David's song of praise: "It is God who arms me with strength" — literally, God who girds me with my amtsah. The word describes God-given martial and moral fortitude.
Amtsah appears in the context of God equipping His servants for battle. David's life was a constant testimony that human strength is borrowed strength — received from God, returned in victory and praise. This is the biblical theology of power: "Not by might nor by power, but by my Spirit, says the Lord Almighty" (Zechariah 4:6). True strength is dependence on God, not independence from Him.