Unrighteousness (adikia) is a betrayal of the Word of truth in the life of a man; it is generally attributable to God’s people who know the truth but walk in a manner that is contrary to it. Judas Iscariot received the “wages of his unrighteousness” (Acts 1:18); while he knew the truth he betrayed it.
Paul wrote to the Romans concerning those who “suppressed the truth in unrighteousness” (Romans 1:18); that is, they knew the truth but refused to obey it. There were also those who disobeyed the truth and were “persuaded” into unrighteousness;
“But to those from self-interest and disobeying the truth but being persuaded to unrighteousness, anger and wrath” (Romans 2:8).
These people are persuaded into unrighteousness by those described as “workers of unrighteousness”.
“’We ate and drank in Your presence, and You taught in our streets’; and He will say, ‘I tell you, I do not know where you are from; depart from Me, all you workers of unrighteousness’” (Luke 13:26-27).
Unrighteousness is the work of the spirit of the world who leads believers into carnality and worldliness. At its heart, unrighteousness is a falling away from God’s ways in favour of one’s own ways; it is a failure to take a firm grip on “the love of the truth so as to be saved” thus leaving one open to the “deception of unrighteousness” (2 Thessalonians 2:10).
The seal of the Lord is this, according to Paul;
“Let everyone who names the name of the Lord abstain from unrighteousness” (2 Timothy 2:19).
He goes on to tell the Corinthians that the unrighteous shall not inherit the kingdom of God (1 Corinthians 6:9). In the following passages he lists some of those who are included amongst the unrighteous; those who are immoral, the idolatrous, adulterers, effeminates, homosexuals, thieves, the greedy, drunkards, abusive persons and extortionists. Whether or not one is, for example, immoral or idolatrous, is a judgement that God makes using His own interpretation, not man’s, as to what constitutes immorality or idolatry.
All of these acts of unrighteousness identified by Paul in his epistle to the Corinthians are to do with the flesh; in terms of modern Christianity, we might add unbelief, pride, vanity, self-righteousness, self-confidence, love of worldly luxuries, unholy thoughts and imaginations, as well as fear of man, not God.