"You shall do to him as he thought to have done to his brother"—Deuteronomy 19:19.
We are commanded to punish false witnesses by sentencing them to the exact punishment they wished to impose upon their innocent fellow. If their testimony was intended to expropriate money, they must pay the amount they wished the other to lose. If their testimony was intended to impose upon the defendant corporeal or capital punishment, they are the ones flogged or put to death.