Exploring the Meaning of Kakopoieo in Greek

κακοποιέω means “to do evil/harm.” It appears in Jesus’ Sabbath questions about whether one may “do harm,” and in two later letters that contrast doing evil with doing good.

Root and Related Words

κακοποιέω corresponds to the related word kakopoios (κακοποιός), “wrongdoing” (Strong’s G2555).

Occurrences

Mark 3:4: He said to them, “Is it lawful on the Sabbath day to do good, or to do harm? To save a life, or to kill?” But they were silent.

Here the verb is placed in a sharp either-or alongside “to do good,” and it is immediately clarified by the paired alternatives “To save a life, or to kill?” The question frames “to do harm” as an act that stands over against preserving life. In the scene, the issue is not presented as a neutral technicality about Sabbath rules; it is driven toward the moral weight of what one’s action (or refusal to act) amounts to when a life is at stake. The silence of the hearers leaves the question hanging in moral terms: the contrast between beneficent action and harmful action is left unanswered by them, but not softened.

Luke 6:9: Then Jesus said to them, “I will ask you something: Is it lawful on the Sabbath to do good, or to do harm? To save a life, or to kill?”

This parallel uses the same contrast, again setting “to do harm” opposite “to do good,” and again tightening it with “To save a life, or to kill?” The verb functions as a moral category within a legal question (“Is it lawful…?”): the point of inquiry is not merely whether an action is permitted, but what kind of action it is—life-saving or life-taking. The structure of the question treats “doing harm” as the negative pole that cannot be cordoned off from real outcomes. By placing it in the context of Sabbath lawfulness, the sentence forces the listener to weigh harm as something that can be implicated even under the cover of religious scruple.

1 Peter 3:17: For it is better, if it is God’s will, that you suffer for doing well than for doing evil.

In this exhortation the verb appears in the phrase “for doing evil,” contrasted with “doing well.” The statement compares two kinds of suffering: suffering that results from “doing well” and suffering that results from “doing evil.” The verb therefore contributes a moral explanation for why hardship comes, and it marks a decisive difference between suffering that accompanies right conduct and suffering that is the fitting consequence of harmful conduct. The added condition “if it is God’s will” is attached to the first case (“that you suffer for doing well”), so “doing evil” is not portrayed as something aligned with God’s will; it is simply the inferior alternative when suffering is in view.

3 John 1:11: Beloved, don’t imitate that which is evil, but that which is good. He who does good is of God. He who does evil hasn’t seen God.

Here the verb is part of a direct moral appeal centered on imitation: “don’t imitate that which is evil, but that which is good.” The following lines press the point into personal characterization: “He who does good is of God. He who does evil hasn’t seen God.” In this setting κακοποιέω is not used in a single disputed case or hypothetical; it describes a pattern of action that aligns with “evil” as a whole. The verb functions as the behavioral side of a spiritual diagnosis: the one who “does evil” is described as one who “hasn’t seen God.” Thus the word carries the sense of harmful action as evidence of one’s orientation, not merely a momentary lapse in conduct.

Sense and Usage

Across these four passages, “to do evil/harm” is consistently framed by antithesis: it is set against doing good (Mark 3:4; Luke 6:9), doing well (1 Peter 3:17), and imitating what is good (3 John 1:11). The word’s force is sharpened by the way the surrounding clauses define the stakes. In the Sabbath questions, “harm” is not left vague; it is placed next to “kill,” so that the term is heard against the most concrete boundary of human action—whether one’s course leads toward preserving life or taking it. In the letter texts, the same term becomes a moral descriptor that explains the meaning of suffering (1 Peter 3:17) and the spiritual seriousness of one’s manner of life (3 John 1:11).

The occurrences show that the verb can function in at least two kinds of discourse. First, it can appear in a probing question designed to expose the moral content of a contested decision (Mark 3:4; Luke 6:9). There it operates as the negative option that a listener must reckon with: if one is not doing good in a situation where life is in view, what does that choice amount to? Second, it can appear in straightforward ethical instruction (1 Peter 3:17; 3 John 1:11). There it helps draw a boundary around conduct that is unworthy: it is the kind of action for which suffering is not “better,” and it is the kind of action that should not be imitated.

In each passage, the verb’s sense is relational rather than abstract: harm is conceived in terms of what it does to life, to others, and to one’s standing. Mark and Luke place the term in the pressure point between lawfulness and moral outcome, making “harm” a category that cannot be excused by an appeal to the calendar. First Peter places it in the comparison of two kinds of suffering, showing that harm is not merely a private failing but a kind of behavior that changes the moral meaning of one’s hardship. Third John uses it to describe a person’s practiced behavior in contrast to good, treating “doing evil” as the opposite of the conduct that belongs with God.

Imagery in Context

The strongest concrete imagery attached to κακοποιέω in these texts is the life-and-death pair that accompanies it: “To save a life, or to kill?” (Mark 3:4; Luke 6:9). That pairing anchors “harm” in tangible consequences rather than in mere intent or theory. The letters then carry that moral clarity into everyday discipleship: actions described as “doing well” and “doing good” stand in open contrast to actions that are harmful, and the contrast is presented as decisive for how suffering is evaluated (1 Peter 3:17) and for whom one imitates and knows (3 John 1:11).

Sources: Lexical data from Strong’s Exhaustive Concordance and the Translators Brief Lexicon of Extended Strongs for Greek (STEPBible, CC BY). Occurrence data from the Translators Amalgamated Greek New Testament (STEPBible, CC BY). Scripture quotations from the World English Bible (public domain).