to burn: to be on fire, to set alight, and so to consume, eat down, or sweep something completely away
At its center this word is the act of fire. Something blazes, or someone kindles it, and the picture moves naturally from the flame itself to what the flame does. A fire does not just glow; it eats, devours, and leaves nothing. So the same word that says a bush is on fire also says an enemy army is burned up, a field is grazed down to bare ground, and an evil thing is cleared out of the land.
The whole range hangs together as one idea: total consumption. To burn is to use up entirely, and to use up entirely is to remove. That is why the word can describe cattle eating a vineyard until nothing is left (the same effect as fire), and why it became Israel's standard term for purging evil. When the law says to burn the evil out from your midst, it does not mean a literal bonfire; it means to wipe the wrong away as thoroughly as fire wipes away stubble.
The word is also the Bible's favorite image for anger, especially God's. Wrath is fire that catches, blazes, and cannot be put out. This is not a separate meaning but the same fire seen as an emotion: it kindles, it burns hot, it consumes.
The senses below trace that movement, from the flame itself, to what is set alight, to what is consumed, to what is cleared away.