At the mouth, i.e. upon the testimony delivered upon oath before the magistrates. Three witnesses, to wit, credible and competent witnesses. The Jews rejected the testimonies of madmen. children, women, servants, familiar friends, or enemies, persons of dissolute lives and evil fame.
Related Commentaries of Deuteronomy 17:6
Deuteronomy 17:6
6 At the mouth of two witnesses, or three witnesses, shall he that is worthy of death be put to death; but at the mouth of one witness he shall not be put to death.