Lust Is Adultery in the Heart

Matthew 5:27-30 extends the prohibition of adultery from the completed sexual act to intentional desire. The key construction is pros to epithymēsai autēn, commonly rendered "with lustful intent" or "in order to desire her." The verb epithymeō can denote desire generally and is not inherently sexual, but here the context is the command against adultery. The syntax therefore points not merely to noticing another person's attractiveness but to looking in a way oriented toward coveting or sexual possession. The language also echoes the Decalogue's prohibition against coveting a neighbor's wife.

The phrase "has already committed adultery with her in his heart" exemplifies Matthew's movement from external action to intention. "Heart" in biblical anthropology denotes the center of thought, desire, and volition rather than emotion alone. The saying is directed grammatically toward a male observer and a woman who is the object of desire, reflecting the social setting of the formulation, though the moral logic concerns adulterous intention rather than one gender uniquely.

The commands to tear out an offending eye and cut off an offending hand are conventionally understood as deliberate hyperbole. Self-mutilation would not solve the inner problem already located in the heart, and Jewish law itself restricted bodily mutilation. The images intensify the seriousness of removing causes of sin. Similar language recurs in Matthew 18:8-9, where the same contrast between losing a body part and being thrown into Gehenna appears.

Matthew 5 opens the Sermon on the Mount, the first of the Gospel's major teaching discourses. Jesus ascends a mountain, sits in the posture of a teacher, and addresses disciples in the presence of the crowds introduced at the end of chapter 4. The chapter moves from the Beatitudes to images of salt and light, then to a programmatic statement about Jesus' relation to the Law and the Prophets. Six subsequent units illustrate the kind of righteousness Jesus demands by treating murder and anger, adultery and desire, divorce, oaths, retaliation, and love of enemies.

The chapter's central interpretive question is how Jesus' teaching relates to Israel's Torah. Matthew explicitly denies that Jesus abolishes the Law and instead speaks of fulfilling it, while the repeated formula "you have heard ... but I say to you" presents Jesus as an authoritative interpreter whose demands reach beyond external conformity to dispositions, intentions, and reconciled relationships. The chapter therefore develops themes introduced earlier in Matthew: kingdom, righteousness, fulfillment, discipleship, and Jesus' distinctive authority.