Regard not them that have familiar spirits, neither seek after wizards, to be defiled by them: I am the LORD your God.

Wesley's Notes

19:31 Wizards - Them that have entered into covenant with the devil, by whose help they foretel many things to come, and acquaint men with secret things. See Lev 20:27 Deu 18:11 1Sam 28:3,7,9 2Kings 21:6.

Jamieson-Fausset-Brown Bible Commentary

31. Regard not them that have familiar spirits-The Hebrew word, rendered "familiar spirit," signifies the belly, and sometimes a leathern bottle, from its similarity to the belly. It was applied in the sense of this passage to ventriloquists, who pretended to have communication with the invisible world. The Hebrews were strictly forbidden to consult them as the vain but high pretensions of those impostors were derogatory to the honor of God and subversive of their covenant relations with Him as His people.

neither seek after wizards-fortunetellers, who pretended, as the Hebrew word indicates, to prognosticate by palmistry (or an inspection of the lines of the hand) the future fate of those who applied to them.

Matthew Henry's Concise Commentary

19:1-37 laws. - There are some ceremonial precepts in this chapter, but most of these precepts are binding on us, for they are explanations of the ten commandments. It is required that Israel be a holy people, because the God of Israel is a holy God, ver. 2. To teach real separation from the world and the flesh, and entire devotedness to God. This is now the law of Christ; may the Lord bring every thought within us into obedience to it! Children are to be obedient to their parents, ver. 3. The fear here required includes inward reverence and esteem, outward respect and obedience, care to please them and to make them easy. God only is to be worshipped, ver. 4. Turn not from the true God to false ones, from the God who will make you holy and happy, to those that will deceive you, and make you for ever miserable. Turn not your eyes to them, much less your heart. They should leave the gleanings of their harvest and vintage for the poor, ver. 9. Works of piety must be always attended with works of charity, according to our ability. We must not be covetous, griping, and greedy of every thing we can lay claim to, nor insist upon our right in all things. We are to be honest and true in all our dealings, ver. 11. Whatever we have in the world, we must see that we get it honestly, for we cannot be truly rich, or long rich, with that which is not so. Reverence to the sacred name of God must be shown, ver. 12. We must not detain what belongs to another, particularly the wages of the hireling, ver. 13. We must be tender of the credit and safety of those that cannot help themselves, ver. 14. Do no hurt to any, because they are unwilling or unable to avenge themselves. We ought to take heed of doing any thing which may occasion our weak brother to fall. The fear of God should keep us from doing wrong things, though they will not expose us to men's anger. Judges, and all in authority, are commanded to give judgment without partiality, ver. 15. To be a tale-bearer, and to sow discord among neighbours, is as bad an office as a man can put himself into. We are to rebuke our neighbour in love, ver. 17. Rather rebuke him than hate him, for an injury done to thyself. We incur guilt by not reproving; it is hating our brother. We should say, I will do him the kindness to tell him of his faults. We are to put off all malice, and to put on brotherly love, ver. 18. We often wrong ourselves, but we soon forgive ourselves those wrongs, and they do not at all lessen our love to ourselves; in like manner we should love our neighbour. We must in many cases deny ourselves for the good of our neighbour. Ver. 31: For Christians to have their fortunes told, to use spells and charms, or the like, is a sad affront to God. They must be grossly ignorant who ask, What harm is there in these things? Here is a charge to young people to show respect to the aged, ver. 32. Religion teaches good manners, and obliges us to honour those to whom honour is due. A charge was given to the Israelites to be very tender of strangers, ver. 33. Strangers, and the widows and fatherless, are God's particular care. It is at our peril, if we do them any wrong. Strangers shall be welcome to God's grace; we should do what we can to recommend religion to them. Justice in weights and measures is commanded, ver. 35. We must make conscience of obeying God's precepts. We are not to pick and choose our duty, but must aim at standing complete in all the will of God. And the nearer our lives and tempers are to the precepts of God's law, the happier shall we be, and the happier shall we make all around us, and the better shall we adorn the gospel.