to go down: to move from a higher place to a lower one, and (with an object) to bring something down
At its core this is the plainest verb of downward motion in the Hebrew Bible. A person goes down a road, water runs down a slope, fire falls from the sky, a body sinks into the grave. The same single idea covers them all: leaving a higher place for a lower one.
The word fans out into a few recognizable settings without ever changing its core. People go down to places that sit lower on the map or lower in importance, and Hebrew fixed certain of these as set expressions: one always goes down to Egypt and down to the sea, and an army goes down to give battle. Natural things descend too, so rain, dew, and fire come down from heaven, and tears run down a grieving face. Most solemnly, the dead go down to the grave, the world below.
When the word takes an object it simply adds a mover: instead of going down oneself, one brings or takes someone or something down. The brothers bring Benjamin down to Egypt, God brings an enemy down, a corpse is taken down from a gallows. This is the same descent, now caused by an agent, which is why it belongs with the rest rather than standing apart as a separate idea.
The pull of the word is almost always downward in a way the reader can feel: away from the high ground, away from the holy mountain, away from life, toward Egypt, toward the sea, toward death. Its natural opposite is the verb for going up, and the Bible often pairs the two.