should we go

The word "we" refers to Ahab, Jehoshaphat, and their armies but not to Micaiah. (See: rc://en/ta/man/jit/figs-exclusive)

will give it into the hand of the king

Here the word "hand" refers to power. Alternate translation: "will allow the king to capture it" (See: rc://en/ta/man/jit/figs-metonymy)