18:18 Neither shalt thou take a wife to her sister, to {i} vex [her], to uncover her nakedness, beside the other in her life [time].
(i) By seeing your affection more bent to her sister than to her.
18:18 Thou shalt not take a wife to her sister - Perhaps this text doth not simply forbid the taking one wife to another, but the doing it in such a manner or for such an end, that he may vex or punish, or revenge himself of the former; which probably was a common motive amongst that hardhearted people to do so.
18:1-30 Unlawful marriages and fleshly lusts. - Here is a law against all conformity to the corrupt usages of the heathen. Also laws against incest, against brutal lusts, and barbarous idolatries; and the enforcement of these laws from the ruin of the Canaanites. God here gives moral precepts. Close and constant adherence to God's ordinances is the most effectual preservative from gross sin. The grace of God only will secure us; that grace is to be expected only in the use of the means of grace. Nor does He ever leave any to their hearts' lusts, till they have left him and his services.
