בוא bw' "enter, go in(to)" a common word. The qal usually has an even wider range of meaning than the English "go in(to)". In Amos these meanings include 4:2; 5:9 & 6:1 "come (to/upon)". In Am 4:1 (and the second occurrence in 4:4) the hiphil means "bring" and at 8:9 even "cause (the sun) to set"! At Am 5:5 it is one of several movement words used together with similar and contrasting meanings which help to build up the "movement" of the verse.