There are two witnesses of the existence of God that all people on the face of the earth have—one is the outward witness of creation and the other is the inward witness of the conscience. There is a built-in knowledge of God. Creation and conscience only bring us to the fact of God.
Romans 1:20-21 says, “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.”
And how is the righteousness of God revealed? From faith to faith. Romans 1:17 says, “For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith.”
God speaks to a man and man responds, “God, I want to know You and I need to know You. I believe that You exist.” That’s faith. And he goes from faith to faith. God gives him more light and that light increases his faith. He steps in the light until he comes to the Lord Jesus Christ.
I believe with all my heart that there’s never been a person who died without some opportunity to have received Christ, had they lived up to the light that God gave them.