9 But thou shalt surely kill him; thine hand shall be first upon him to put him to death, and afterwards the hand of all the people.
[AD 391] Pacian of Barcelona on Deuteronomy 13:9
Do you see then that this was not said about penitents but about those who not only themselves persevere in wickedness but also do not cease to put obstacles in our way? It is these very ones, however dear they may be, that must be relinquished. However useful they seem, they must be abandoned.

[AD 1781] Richard Challoner on Deuteronomy 13:9
Presently put him to death: Not by killing him by private authority, but by informing the magistrate, and proceeding by order of justice.