In times past Enoch walked with God.
Noah walked with God.
“And when Abram was ninety years old and nine, the LORD appeared to Abram, and said unto him, I am the Almighty God; walk before me, and be thou perfect.” (Gen 17:1)
To walk with God is to know Him; those who know Him obey Him. They are deemed to be perfect not because of sinlessness but because of obedience borne out of a contrite heart.
Those who did not walk with God did so from unbelief. Hence they were referred to as unbelievers.
Old Testament prophets described unbelievers as children of Belial; epitomes of wickedness and ungodliness.
John the Baptist described them as brood of vipers.
Jesus called them hypocrites, children of the devil.
Under the New Covenant, those who do not submit to the Lordship of Jesus Christ do not believe in the efficacy of the sacrifice He made on the cross of Calvary. They are unbelievers.
Paul said unbelievers are darkness.
Peter described the unrighteous as servants of corruption with eyes full of adultery; dogs.
For James sinners are adulterers and adulteresses, enemies of God.
John calls them lovers of the world; enemies of God; sinners with the devil.
Jude was incisive in his description (Jude 8-23). He called them filthy dreamers, brute beasts, clouds without water, trees without fruit, twice dead, pulled up by the roots; raging waves of the sea, wandering stars for whom is reserved the blackness of darkness forever; ungodly sinners, grumblers, complainers, lustful, mockers and scoffers, sensual persons, who cause divisions, not having the Spirit but are already in the fires of hell.
Unbelievers should not be envied but pitied for they do not know what awaits them in the fires of hell if they fail to repent while there is time and receive God’s gift of eternal life that is in Christ Jesus.
Wisdom is profitable to direct in the affairs of this life.