This the Lord spake to forbid any putting to death. For we ought not to kill an heretic, seeing that so a neverending war would be introduced into the world; and therefore He says, “Lest ye root out with them the wheat also;” that is, if you draw the sword and put the heretic to death, it must needs be that many of the saints will fall with them.
Hereby He does not indeed forbid all restraint upon heretics, that their freedom of speech should be cut off, that their synods and their confessions should be broken up — but only forbids that they should be put to death.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).