In the evil day - The day of temptation; the day when you are violently assaulted.
And having done all, to stand - Margin, “or overcome.” The Greek word means, to work out, effect, or produce; and then to work up, to make an end of, to vanquish. Robinson, Lexicon. The idea seems to be, that they were to overcome or vanquish all their foes, and thus to stand firm. The whole language here is taken from war; and the idea is, that every foe was to be subdued - no matter how numerous or formidable they might be. Safety and triumph could be looked for only when every enemy was slain.