Who was the first man saved on Earth? To answer this, let us start today and work backward. We know that salvation today depends on a right relationship with God through faith in Jesus Christ. It is certainly easier for some to come to this relationship than others, depending on circumstance. For instance, it is easier to become a Christian if one grows up in a good Christian home. But even under the most difficult conditions, people still find God. It has even been observed that some primitive peoples, with no knowledge of civilization, contain Christians when missionaries first reach them. This doesn't happen often, but it does happen. In addition, and moving back in time now, did you ever wonder how the wise men from the East -- whom we honor every Christmas -- knew so much about Jesus? And many centuries before Jesus, the Jewish people placed their hope in God's plan of salvation, which ultimately rested on the Messiah, Christ.
Jesus said, "No one can come to me unless the Father who sent me draws him to me; and I will raise him to life on the last day. The prophets wrote, 'All men will be taught by God.' Everyone who hears the Father and learns from him comes to me" (John 6:44,45). Jesus' words are eternal, and they are not necessarily confined in time and space. It is possible, therefore, to come to a knowledge of salvation at any time and place: this knowledge proceeding directly and solely from God. It is more difficult to find God without the help of our fellow man's personal witness, books, etc., but it can happen.
Salvation is for all men, and our knowledge of the oldest fully modern people comes from those living on the southern tip of Africa 100,000 years ago. It is possible that, out of a great search for truth, one of these ancients came to a knowledge of God's interest in mankind and provision of a saviour, sin, and the need for repentance and relationship with God. This probably did happen, maybe not exactly 100,000 years ago, but within tens of thousands of years on either side of this date. If the first saved man did not occur at this time, then he appeared sometime between this time and the time when God spoke to the first great Jewish prophets (thousands of years ago).
It was difficult for God to first reach man not because God intended life to be this way, but because great supernatural powers (Satan and demons), whom He created, turned against Him in the beginning, even before the Big Bang.