People will live in the Lord and the Lord in them (John 14:20; 15:1–5; 17:23), a situation that is brought about by faith.
To both Jews and Greeks Paul proclaimed repentance before God and belief in our Lord Jesus Christ. (Acts 20:21)
I am the way, the truth, and the life. No one comes to the Father except through me. (John 14:6)
Those who believe in the Son believe in the Father, since as we said above, the Father is in the Son like a soul in a body. The following passages make this clear:
If you had known me you would have known my Father also. (John 8:19; 14:7)
Those who see me see the One who sent me. (John 12:45)
Those who receive me receive the One who sent me. (John 13:20)
This is because no one can see the Father and live (Exodus 33:20), which is why the Lord says,
No one has ever seen God. The only begotten Son, who is close to the Father’s heart, has made him visible. (John 1:18)
No one has seen the Father except the One who is with the Father. He has seen the Father. (John 6:46)
You have never heard the voice of the Father or seen what he looks like. (John 5:37)
There are those of course who know nothing about the Lord, such as most people who are in those two great parts of the world called Asia and Africa, as well as in the Indies, for example. If they believe in one God and follow the principles of their religion in their lives they are saved by their faith and by their life. Spiritual credit or blame applies only to those who know; it does not apply to those who do not. We do not blame the blind for tripping. As the Lord says, “If you had been blind you would have had no sin; but now that you say you see, your sin remains” (John 9:41).
from True Christianity, Section 107