Paul’s Letter to the Romans assures us that God has left no one without some knowledge of himself. “For what can be known about God is evident to them, because God made it evident to them. Ever since the creation of the world, his invisible attributes of eternal power and divinity have been able to be understood and perceived in what he has made” (1:19-20).
Though all non-Christian religions contain error, they also have elements of God’s truth. Wherever God reveals His truth to any degree, He always reveals through His Son. “All things have been handed over to me by my Father. No one knows the Son except the Father, and no one knows the Father except the Son and anyone to whom the Son wishes to reveal him” (Mt 11:27).
Whenever a non-Christian prays to God, whatever of truth he knows and whatever of true love for God he reveals, that person is in fact praying through the Jesus Christ he does not know. Whatever of God’s truth is in that person’s mind and attitude must be pleasing to God.
The Church teaches that persons who truly love and serve God as best they can know Him can be saved. But they are saved by the truth they profess, not the error which their religions have imparted to them.
That truth comes to them through God’s Son, Jesus Christ. Therefore the Church has to proclaim that, ultimately, no one can be saved except through Jesus Christ.