Word studies · Hebrew · Strong's H3581
כֹּחַ · kôach · appears 126 times in the Old Testament
In one line: Strength to act and endure — God's, when yours runs out.
But those who wait upon the LORD will renew their strength; they will mount up with wings like eagles; they will run and not grow weary, they will walk and not faint.
Isaiah 40:31
Koach is strength — the capacity to act or endure, whether a person's, a nation's, or God's inexhaustible power.
Koach names physical strength, ability, and the resources a person or people can bring to bear. Scripture repeatedly measures human koach against God's and finds it finite: youths grow weary, but those who wait on the LORD renew their strength.
Koach derives from an unused root meaning to be firm, and its uses range widely — bodily vigour, the produce a field has strength to yield, the means someone commands. Strong's notes that the same consonants even name a large lizard, presumably for its hardiness.
Hebrew tends to speak of strength as something you have and can run out of, rather than a quality you possess in the abstract. That gives verses like “not by might, nor by power, but by my Spirit” their sharpness: they are about which supply you are drawing on.
Koach (H3581) appears 117 times in the Hebrew Bible, including Zechariah's “not by might, nor by power, but by my Spirit, says the LORD of hosts.”
Setting human strength against divine strength is one of Scripture's steady rhythms: God does not need ours, and gives His to those who admit they have none. The New Testament's “my power is made perfect in weakness” is the same theology in Greek.
Notice where you are running on your own reserves and calling it faithfulness. Choose one task this week you will not attempt before asking God for strength you do not have.
vigor, literally (force, in a good or a bad sense) or figuratively (capacity, means, produce); also (from its hardiness) a large lizard
When you till the ground, it will no longer yield its produce to you. You will be a fugitive and a wanderer on the earth.”
Genesis 4:12But I have raised you up for this very purpose, that I might display My power to you, and that My name might be proclaimed in all the earth.
Exodus 9:16the gecko, the monitor lizard, the common lizard, the skink, and the chameleon.
Leviticus 11:30But Moses said to the LORD, “The Egyptians will hear of it, for by Your strength You brought this people from among them.
Numbers 14:13Because He loved your fathers, He chose their descendants after them and brought you out of Egypt by His presence and great power,
Deuteronomy 4:37still as strong today as I was the day Moses sent me out. As my strength was then, so it is now for war, for going out, and for coming in.
Joshua 14:11Press and hold strength in any chapter and this study opens on the verse you are reading, with the lexicons, every occurrence and the commentaries beside it. The Bible is free to read.
Scripture quoted from the Berean Standard Bible, public domain. Strong's definitions are public domain. Counts come from The Pillar's own tagged text.