Deuteronomy 19:18-20

19:18 The judges will thoroughly investigate the matter, and if the witness should prove to be false and to have given false testimony against the accused, ¹  19:19 you must do to him what he had intended to do to the accused. In this way you will purge ²  evil from among you. 19:20 The rest of the people will hear and become afraid to keep doing such evil among you.

[19:18]  ¹ tn Heb “his brother” (also in the following verse).

[19:19]  ² tn Heb “you will burn out” (בִּעַרְתָּ, bi’arta). Like a cancer, unavenged sin would infect the whole community. It must, therefore, be excised by the purging out of its perpetrators who, presumably, remained unrepentant (cf. Deut 13:6; 17:7, 12; 21:21; 22:21-22, 24; 24:7).