John Calvin Commentary Deuteronomy 28:19

"Cursed shalt thou be when thou comest in, and cursed shalt thou be when thou goest out." — Deuteronomy 28:19 (ASV)

Cursed shalt thou be when thou comest in. God here pronounces that all their undertakings would be unsuccessful; for "going out and coming in" signifies their various actions and the whole course of their life. This is more clearly expressed in the next verse, where He proclaims misfortune for them in all their affairs, meaning that God would confound and spoil whatever they might undertake.

The words ²³⁷מהומה, mehumah, and מגערת, migegnereth, are indeed variously explained. Still, the sum of it is this: God would be against them, so as to thwart and overthrow all their counsels and labors. Therefore, we are taught that all human endeavors are useless and vain unless they seek success from God.

²³⁷ מהומה, “Vexation.” — A V. “Bruising, trampling, destruction.” — Robertson, Clavis Pentateuchi.