1John 3:8 He that commits sin is of the devil; for the devil sins from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil.
‘He that commits sin is of the devil’ every man who sins is of the devil (3:8; John 8:44). Christ died to destroy and cancel all the works of the devil for believers in this age, and to give complete mastery over them (Mark 16:17-18; Luke 10:19; John 14:12; Col. 2:14-17; 1Pet. 2:24).
‘The Son of God was manifested’ Jesus came as a man – a lowly servant of all to set the right example of how men can be like God. He came and lived as God would live among men so that men could learn to live like God. He literally “emptied Himself” (Php. 2:9) and took the form of a servant instead of the form of a sovereign. He humbled Himself from deity to humanity and from humanity to infamy, taking on Him the sins of the world and redeeming fallen man to His original dominion.
The works of the devil – that Christ came to destroy – can be summarized as follows: Sin, especially rebellion started with him (Gen. 3:2; 2Cor. 11:3), works of darkness, including moral sedition and sexual perversion (Rom. 1:1-32; Eph. 5:11; 6:12; Acts 16:18). He causes works of wickedness (Col. 1:21) and spiritual blindness (2Cor. 4:4). He steals the Word of God from men’s minds (Matt. 13:19) through deceptions and false religions (2Cor. 11:14; 1Tim. 4:1-16; Rev. 12:9). He kills and destroys men lives (John 8;44; 10:10). He sows tares, tempts, and sifts saints (Matt. 4:3; 13:25; Luke 22:31). He promotes counterfeit worship and miracles (1Cor. 10:20; 2Thess. 2:8-12). He causes storms (Job 1:18-19; Eph. 2:2), rules nations (Matt. 4:8-9; Dan. 10:1-21), executes death (Heb. 2:14-15), accuses the brethren (Rev. 12:10), hinders prayers (Dan. 10:12-21) and he opposes the gospel (Eph. 6:1-18). He supervises demons (John 12:31), fallen angels (Rev. 12:7-12), and fallen man (3:8; John8:44; Eph. 2:2). He causes sickness and disease, infirmities, lunacy and mania (Matt. 4:23-24; 8:17; 9:32-33; 15:22; 17:14-21; Mark 5:1-18; Luke 13:16; John 10:10; Acts 10:38). He urges suicides (Matt. 17:15; John 10:10), agitates lusts (John 8:44; Eph. 2:1-3), promotes lying and false prophecy (1Kin. 22:1-53; Matt. 24:11, 24; 2Cor. 11:13-15), and propagates false doctrines (1Tim. 4:1-16; 2Tim. 4:1-22; 2Thess. 2:1-17; Rev. 13:1-18). He oppresses men (Acts 10:38), persecutes Christians and wars on saints (Eph. 6:10-18; 1Pet. 5:8-9).
Christ came to take away our sins and if we still have them, it is proof we have not truly repented of them as most men don’t really want to be done with sin. If you say you abide in Him you will not sin (3:5-7).