The faith of the new heaven and the new church in universal form is this: The Lord from eternity, who is Jehovah, came into the world to gain control over the hells and to glorify his own human nature. If he had not done this, not one mortal could have been saved; those who believe in him are saved.
I say “in universal form” because this concept is universal to the faith and something universal to the faith is going to be present in each and every aspect of it. It is universal to the faith to believe that God is one in essence and in person, to believe that in God there is a divine Trinity, and to believe that the Lord God the Savior Jesus Christ is God. It is universal to the faith to believe that if the Lord had not come into the world not one mortal could have been saved. It is universal to the faith to believe that the Lord came into the world to separate hell from the human race, and that he accomplished this by repeatedly doing battle with hell and conquering it. In this way he gained control over it, forced it back into the divine design, and made it obey him. It is universal to the faith to believe that he came into the world to glorify the human nature he took on in the world, that is, to unite it to its divine source. This is how he keeps hell eternally in its place and in obedience to himself. Since this could not have been accomplished except by allowing his human nature to be tested, including even the ultimate test, the suffering on the cross, therefore he underwent that experience. These are universal points of faith regarding the Lord.
For our part, it is universal to the faith that we believe in the Lord, for our believing in him gives us a partnership with him, and through this partnership comes salvation. To believe in him is to have confidence that he saves; and because only those who live good lives can have such confidence, this too is meant by believing in him. In fact, the Lord says in John: “This is the will of the Father, that everyone who believes in the Son has eternal life” (John 6:39–40). And in another passage,
“Those who believe in the Son have eternal life. But those who do not believe the Son will not see life; instead the anger of God remains on them” (John 3:36).
from True Christianity, Volume 1, Section 2