Self-control relates to the passions (such as anger or love), the appetites (for food, sex, etc.), and the will (as illustrated by impulsive decisions). The lack of self-control is a mark of a fool. He is like a city . . . left without walls, that is, with no means of defense against enemies. (https://www.crossway.org/articles/10-key-bible-verses-on-self-control/)

Self-control is the discipline given by the Holy Spirit that allows Christians to resist the power of the flesh (cf. Gal. 5:17). Against such things there is no law, and therefore those who manifest them are fulfilling the law—more than those who insist on Jewish ceremonies, and likewise more than those who follow the works of the flesh surveyed in Gal.5:19–21. Again, Christ and the Spirit (Gal. 5:25) come together as the source of the believer’s life. Christians have crucified the flesh, or died with Christ to sin (see Gal. 6:14; Rom. 6:4–6). Now that the old order of things has passed away for believers, their old sinful selves that belonged to that order have crumbled as well—so they should pay no attention to them. “Flesh” here should not be understood to mean physical bodies but rather fallen, sinful human nature with all its desires.

Jesus uses hyperbole (intentional overstatement) to show the seriousness of sin and the fact that nothing, even things of greatest importance to humans such as a hand, foot, or eye, can be more important than God. “Hand,” “foot,” and “eye” probably also serve as metonymies (where one thing stands for something related to it) for sins that can be committed with these body parts. (E.g., the “hand” may represent theft or murder done by the hand; the “foot” may represent going somewhere to undertake a sinful act; the “eye” may represent coveting, lust, or adultery, as in Matt. 5:27–30.) Of course, Jesus does not mean that people should literally cut off those body parts, for the literal removal of them cannot remove the root of sin in the heart (see Mark 7:20–23; Mark 9:45). Jesus’ words serve as a sober warning concerning the severity of sin, which can lead to hell (Gk. gehenna; see Isa. 66:24) and fire that is not quenched (Mark 8:35–37; Mark 9:47–48).

Hearing and Doing the Word. The central theme of this section is practical Christianity mandated by “the word of truth,” which is the gospel (James 1:18), and characterized by both truly “hearing” and then resolutely “doing” the truth. Obedience is the hallmark of the true child of God. Hearers of the Word. James encourages the church to pursue hearing the word, and to avoid hasty speech and unrighteous anger. James echoes Jewish Wisdom tradition on the misuse of the tongue and the anger that can result (cf. Prov. 10:19; 11:12; 15:1; 17:28). quick to hear. Lack of listening, combined with lack of restraint in speech, leads to ill-tempered action. Slow to anger does not mean that all human anger is sinful (cf. Eph. 4:26), but the quick-tempered, selfish anger of the world (“the anger of man,” James 1:20) betrays lack of trust in God and lack of love for others. The self-reliant anger of man, even when directed against some wrongdoing, fails to recognize that mere human reproach cannot change another person’s heart, and thus it does not produce the righteousness of God; nor indeed is such anger fully righteous itself. God is holy and righteous, requiring that his people emulate his righteous character (e.g., Lev. 19:2; Matt. 5:48; 1 Pet. 1:16). “Righteousness” here is not Pauline legal or forensic righteousness proclaimed in God’s court of law (e.g., see notes on Rom. 3:20; 5:10) but is closer to the usage of the OT (Isa. 61:3) and Jesus (Matt. 3:15; Matt. 5:6, Matt.5:10, Matt. 5:20; Matt.6:1, Matt.6:33; Matt.21:32), in the sense of conducting one’s life by the will of God, according to his standards.

Paul frequently uses athletic metaphors to describe the rigors and single-minded focus of his apostolic work to pursue the advancement of the gospel (see also Phil. 3:12–14; 2 Tim. 4:7–8). The extended metaphor is particularly apt in a letter to Corinth, which was the location of the biennial Isthmian games, at that time second in fame only to the Olympic games. Paul’s stay in Corinth during his second missionary journey (Acts 18) may have overlapped with the games in either A.D. 49 or 51. The perishable wreath was a crown (Gk. stephanos) of foliage (and therefore quick to wither) which was given to the victor in a public athletic contest. Paul thinks of his congregations as the victor’s crown that he will wear on the final day

supplement your faith. Peter exhorts Christians not merely to confess faith in Christ but actually to live as he taught. He is not saying that works are a prerequisite for salvation but rather is arguing that faith must take concrete form in life. All the virtues listed in 2 Peter 1:5–7 are results of faith, so faith is listed first, while love (the ultimate result of faith) is listed last (2 Peter 1:7; cf. 1 Tim. 1:5). Virtue translates Greek aretē. Godliness translates Greek eusebeia, “devoutness, piety, devotion to God” (also in 2 Peter 1:3; 1:7; 3:11; 2 Tim. 3:5).