“Even as Abraham believed God, and it was accounted to him for righteousness.” (Galatians 3:6)
The Salvation that Jesus Christ offers to men is based upon faith in His finished work.
That faith is based upon very specific Truths about Jesus Christ.
These truths are found in very specific written words. Those words are inspired of God. They are inerrant, complete, accurate, and sufficient for a man to know the way of Eternal Life.
When a man believes what God has said in His word, repents of his sins, and places His faith in the sufficiency of Jesus Christ, he is saved. He passes from death to life.