(18) Thou shalt not suffer a witch to live.--The word translated "witch" in this passage is the feminine singular of that rendered by "sorcerers" in Exodus 7:11, and means "a mutterer of charms." The use of the feminine form can only be accounted for by supposing that, practically, witchcraft was at the time mainly professed by females. Whether "witches" had actual help from evil spirits, or only professed to work magical effects by their aid, the sin against God was the same. Jehovah was renounced, and a power other than His invoked and upheld. Witchcraft was as much rebellion against God as idolatry or blasphemy, and deserved the same punishment.

Pulpit Commentary

Verse 18. - Law against witchcraft. Witchcraft was professedly a league with powers in rebellion against God. How far it was delusion, how far imposture, how far a real conspiracy with the powers of evil, cannot now be known. Let the most rationalistic view be taken, and still there was in the practice an absolute renunciation of religion, and of the authority of Jehovah. Wizards (Leviticus 19:31) and witches were, therefore, under the Jewish theocracy, like idolaters and blasphemers, to be put to death.

Matthew Henry's Concise Commentary

22; 1 - 31 Judicial laws. - The people of God should ever be ready to show mildness and mercy, according to the spirit of these laws. We must answer to God, not only for what we do maliciously, but for what we do heedlessly. Therefore, when we have done harm to our neighbour, we should make restitution, though not compelled by law. Let these scriptures lead our souls to remember, that if the grace of God has indeed appeared to us, then it has taught us, and enabled us so to conduct ourselves by its holy power, that denying ungodliness and wordly lusts, we should live soberly, righteously, and godly in this present world, Titus 2:12. And the grace of God teaches us, that as the Lord is our portion, there is enough in him to satisfy all the desires of our souls.

Gill's Exposition of the Entire Bible

Thou shall not suffer a witch to live. Such that had familiar spirits, and conversed with them, and by means thereof got knowledge of many things relating to persons, at least pretending they did; and who did or seemed to do many strange and surprising feats, as even to raise the spirits of departed persons, to converse with them and gain knowledge by them, though in reality they did not, and could not do such things, but used some juggling tricks to deceive the people, and in which they might be assisted by evil spirits; as appears from the case of the witch of Endor, who was surprised at the appearance of Samuel, it being out of the ordinary course of her art and practice really to bring up the spirit of a man deceased, whatever pretensions might be made to it; however, such being deceivers of the people, and leading them into unwarrantable practices, and off of a dependence on God and his providence, and from seeking to him, and asking counsel of him, they are by this law condemned to death, such an one was not to be suffered to live; not that it was lawful for anybody to kill her, or that any private person might or must do it that knew her, or took her to be a witch; but she was to be had before a court of judicature and tried there, and, if found guilty, to be put to death by the civil magistrate: so Jarchi's note is,"but she shall die by the house of judgment;''or the sanhedrim; for these words are spoken to Moses the chief judge, and to those that were under him, and succeeded him and them; though the Targum of Jonathan prefaces them thus:"and my people, the children of Israel, thou shalt not, &c.''and though only a witch is mentioned, or this is only expressed in the feminine gender, because a multitude of this sort of people were found among women, as Ben Melech observes, and so Aben Ezra; yet wizards, or men that dealt with familiar spirits, are included; and it may be reasonably concluded from hence, that if women, who generally have more mercy and compassion shown them, yet were not suffered to live when found criminal in this way, then much less men: and this law is thought by some to follow upon the other, concerning enticing and lying with a virgin not betrothed; because such sort of persons were made use of to entice and decoy maids to gratify the lusts of men.

BibleApps.com