1 John 4:15

¹³ By this we know that we remain in Him, and He in us: He has given us of His Spirit.

¹⁴ And we have seen and testify that the Father has sent His Son to be the Savior of the world.

If anyone confesses that Jesus is the Son of God, God abides in him, and he in God.

¹⁶ And we have come to know and believe the love that God has for us. God is love; whoever abides in love abides in God, and God in him.

¹⁷ In this way, love has been perfected among us, so that we may have confidence on the day of judgment; for in this world we are just like Him.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB: If anyone confesses that Jesus is the Son of God, God abides in him, and he in God.
KJV: Whosoever shall confess that Jesus is the Son of God, God dwelleth in him, and he in God.
WEB: Whoever confesses that Jesus is the Son of God, God remains in him, and he in God.
ASV: Whosoever shall confess that Jesus is the Son of God, God abideth in him, and he in God.
DARBY: Whosoever shall confess that Jesus is the Son of God, God abides in him, and he in God.
BLB: Whoever should confess that Jesus is the Son of God, God remains in him, and he in God.

ÅB: Den som bekjenner at Jesus er Guds Sønn, i ham blir Gud, og han i Gud.
OTB: Den som bekjenner at Jesus er Guds Sønn, i ham bor Gud, og han i Gud.
B1930: Den som bekjenner at Jesus er Guds Sønn, i ham blir Gud, og han i Gud.

Romans 10:9
that if you confess with your mouth, “Jesus is Lord,” and believe in your heart that God raised Him from the dead, you will be saved.
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Matthew 10:32
Therefore everyone who confesses Me before men, I will also confess him before My Father in heaven.
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1 John 5:5
Who then overcomes the world? Only he who believes that Jesus is the Son of God.
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1 John 3:24
Whoever keeps His commandments remains in God, and God in him. And by this we know that He remains in us: by the Spirit He has given us.
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1 John 4:2
By this you will know the Spirit of God: Every spirit that confesses that Jesus Christ has come in the flesh is from God,
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Philippians 2:11
and every tongue confess that Jesus Christ is Lord, to the glory of God the Father.
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1 John 4:12
No one has ever seen God; but if we love one another, God remains in us, and His love is perfected in us.
Read in context
1 John 5:1
Everyone who believes that Jesus is the Christ has been born of God, and everyone who loves the Father also loves those born of Him.
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