Jesus is offering an implicit argument from Scripture, not just a cultural critique. Although the seventh of the ten commandments declared, "You shall not commit adultery" (Ex 20:14), the tenth commandment declared, "You shall not covet," that is, desire, anything that belongs to your neighbor (Ex 20:17). In the popular Greek version of his day, the tenth commandment began, "You shall not covet your neighbor's wife," and used the same word for "covet" that Jesus uses here for "lust"). . . .In other words, Jesus reads the humanly unenforceable tenth commandment as if it matters as much as the other, more humanly enforceable commandments. In Matthean ethics, if one does not break the letter of the other commandments, but one wants to do so, one is guilty.

. . . .He treats lust as if it is exclusively a sin of the lusting heart, not a sin of letting hair out from under one's covering.

. . . .Jesus is saying that lust, as a form of adultery, merits a capital sentence before the heavenly court: eternal damnation. Thus it is better to tear out one's eye than to keep lusting (5:29). . . .In this context, the hand might refer to self-stimulation, as in similar Jewish texts concerning lust as adultery. . . .Jesus is declaring in a graphic manner that by whatever means necessary, one should cast off this sin (Col 3:5 seems to interpret Jesus' amputation saying thus). One must repent to be ready for the kingdom of heaven (4:17).

. . . .By saying "adultery" Jesus technically addresses only lust for married women. . . .but this is an example that should provoke its hearers to consider related moral issues. Thus, for example, it rules out "fornication of the heart" as well; Israelite law treated premarital sex in part as an offense against one's future spouse and one's partner's future spouse (Deut 22:13-21).

Jesus does not, of course, refer here to passing attraction, "but the deliberate harboring of desire for an illicit relationship". . . .The Greek present tense often bears a continuous sense, and probably does so here: Jesus refers not to noticing a person's beauty, but to imbibing it, meditating on it, seeking to possess it. Paul and most of his Jewish contemporaries prescribed marriage as a helpful antidote to this sin[.]