Therefore, let that abide in you which you heard from the beginning. If what you heard from the beginning abides in you, you also will abide in the Son and in the Father (1 John 2:24).
What did we hear from the beginning? John, who wrote the Gospel of John, the three little books of John, and the book of Revelation could easily point to the first sentence of his writings: John 1:1— In the beginning was the Word, and the Word was with God, and the Word was God. If we follow on down, John further explains in verse 14: And the Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father, full of grace and truth.
God divided Jesus out of Himself. Before the world was, Jesus was. He came out of God. His role is that of the Word. God speaks and Jesus manages what He said. Out of His management we have the Bible. The Holy Spirit also came out of God. His role is to wield the power in and for our lives. These three are one, they always agree, and they are never separate, always together.
Mankind, the precious humanity They created, has a tendency to fall seriously hard into Satan’s trap. In the beginning God flooded the earth and only saved Noah and His family. Later, God the Father wanted to destroy all humanity again, and Moses begged Him not to do that. Again, things got so bad that God didn’t even speak for 400 years. Jesus volunteered to come to the earth as a human being and to pay, with His blood, the price of buying humanity back from the devil.
From our beginnings, we have heard that Jesus died for our sins. When we accept His sacrifice, then what we heard from the beginning abides in us. Then and only then do we have the Father, we have the Son, and we have the Holy Spirit. All three make their home in our spirits.