The rule for witnesses to throw the first stones prevented false accusations. Giving false testimony had serious consequences. Requiring a witness to lead an execution ensured his testimony was reliable. He would feel guilty if he killed an innocent person (see John 8:1–11).
The people would remove evil from among them by executing those whose sins brought guilt to the community of Israel (see “Purge the Evil” Theme Note; compare 1 Corinthians 5:12–13 and study note).