Paul says that “we ourselves” were once “foolish” before we were saved. The word foolish means “unwise” (Ps. 94:8; Rom. 1:22), and we were certainly that! But it can also mean sinful (Ps. 5:5; I Chron. 21:8), and we were certainly that as well! Not all the time, but “sometimes” as Paul says.
The reason he’s reminding us of this is because when most Christians see unsaved people living foolishly in sin, they think it is their job as a Christian to condemn them. And in the context, that’s what Paul’s telling us not to do. Rather than “speak evil” of abortionists and homosexuals, etc., Paul says to remember that you too were sometimes foolish enough to live in sin when you were unsaved.
If you’re thinking it is not speaking evil of homosexuality to say it is wrong if it is wrong, remember that everything Paul said about the high priest was true, but it was speaking “evil” of him to say it because it was not his place to criticize the leader of Israel (Acts 23:1-5). And it’s not our place to criticize sinners for being sinful, it is our place to give them the gospel and teach them the Bible.
Unsaved people are foolish enough to live in sin “for they know not the way of the Lord” (Jer. 5:4). God’s people know His way, however, so if you want to be upset with someone for being sinful, be upset with believers, as Paul was (I Cor. 5:9-12).
True, some unsaved people know the Bible says their sins are wrong and choose to disobey God anyway, but we ourselves were once “disobedient” (3:3). True, some unsaved people have been deceived into thinking their sin isn’t wrong, but we ourselves were once “deceived” (3:3), “serving divers lusts.” In the Bible, slaves were the ones who served, and you wouldn’t criticize a slave for serving his master since he has no choice. Well, unsaved people must serve sin because sin is their master, and they have no choice but to serve sin since everything they do is sin (Pr. 21:4). Believers can choose not to sin—and should (Rom. 6:17,18).
If you’re serving sin, be upset with yourself, not the unsaved!
Malice (3:3) is like prejudice, “extreme hatred for no reason.” You used to be that way all the time, and might still fall into that, but you don’t live in that, so put it off (Col. 3:5-8). Put off envy too, which is stronger than anger (Pr. 27:4) and can rot your bones (Pr. 14:30).
Another reason we shouldn’t condemn unsaved sinners for being sinful is because that’s not what God did when we were sinful (3:4). You didn’t get saved because Christians told you that God hated you because of your sins, you got saved because they told you God loves you and sent His Son to die for your sins. So tell unsaved sinners that instead of condemning them for their sins.
Under the Law, the kindness and love of God toward Israel appeared, but now under grace Paul says it appears “toward man” (3:4). Under the law it appeared to Jewish men by the works of righteousness which they did, works like circumcision, sacrifices, baptism. But now salvation is “no more of works” (Rom. 11:6). Under the law they had to work righteousness to be saved (Ps. 15:1,2), “sacrifices of righteousness” (Deut. 33:19; Ps. 4:5). They also had to walk in “all the commandments and ordinances of the Lord” if they wanted to be “blameless” (Luke 1:6).
But all that changed beginning with the appearing of our Lord (II Tim. 1:8-10)—not His appearing on earth to Israel, but His appearing to Paul (Acts 16:16,17). Under the Law God’s mercy was only available to Israel (Ps. 130:7), and to Gentiles through them. But beginning with Paul, God’s “mercy” (3:5) is available to us Gentiles too, through the washing of regeneration (3:5).
Jews were saved by the washing of water baptism (Heb. 10:22; Acts 22:16), but now we are saved by the washing of justification and sanctification (I Cor. 6:11). “Regeneration” refers to the new birth that is performed “by the Spirit” (3:5 cf. I Cor. 6:11). Once you receive it, you can “serve in newness of Spirit” (Romans 7:6).