“The Lord Jesus shall be revealed from heaven with his mighty angels, in flaming fire taking vengeance on them that know not God” 2Thes 1
When people ask, “What about those who haven’t heard the Gospel?” they are misunderstanding the Gospel.
“The wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness; because that which may be known of God is manifest in them; for God hath shewed it unto them. For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse: because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.” Ro 1
Everyone knows the God and his law, and to keep his law is the whole duty of man (atoning for our sins is not our duty but God’s, our duty is obedience).
“Fear God, and keep his commandments: for this is the whole duty of man.” Ecc 12
No one has any excuse; the only sense in which anyone does not know God is in being willingly ignorant:
“Whosoever sinneth hath not seen him, neither known him.” 1J 3
Those who know not God, which is only through their willing ignorance, it is on them that shall come the vengeance of God in flaming fire. It is in the same sense that Christ, who knows all things, knows them not.
“I never knew you: depart from me, ye that work iniquity.” Mt 7