You must not wrong or oppress a foreigner, for you were foreigners in the land of Egypt. You must not exploit any widow or orphan. If you do abuse them, when they cry out to me, I will surely heed their cry; my wrath will burn against you, and I will kill you with the sword, and your wives shall become widows and your children orphans.
(This is the only commandment given by God in Exodus that comes with an explicit promise of retribution by God Himself.)
-- Exodus 22
When we have done our best, we should wait the result in peace.