By this you know the Spirit of God: Every spirit that confesses that Jesus Christ has come in the flesh is of God,
and every spirit that does not confess that Jesus Christ has come in the flesh is not of God. And this is the spirit of the Antichrist, which you have heard was coming, and is now already in the world.
References for 1 John 4:3
You are of God, little children, and have overcome them, because He who is in you is greater than he who is in the world.
They are of the world. Therefore they speak as of the world, and the world hears them.
We are of God. He who knows God hears us; he who is not of God does not hear us. By this we know the spirit of truth and the spirit of error.
Beloved, let us love one another, for love is of God; and everyone who loves is born of God and knows God.
He who does not love does not know God, for God is love.
In this the love of God was manifested toward us, that God has sent His only begotten Son into the world, that we might live through Him.
In this is love, not that we loved God, but that He loved us and sent His Son to be the propitiation for our sins.
Beloved, if God so loved us, we also ought to love one another.
No one has seen God at any time. If we love one another, God abides in us, and His love has been perfected in us.