20 We know also that the Son of God has come and has given us understanding, so that we may know him who is true. And we are in him who is true by being in his Son Jesus Christ. He is the true God and eternal life.

Read 1 John 5:20 Using Other Translations

And we know that the Son of God is come, and hath given us an understanding, that we may know him that is true, and we are in him that is true, even in his Son Jesus Christ. This is the true God, and eternal life.
And we know that the Son of God has come and has given us understanding, so that we may know him who is true; and we are in him who is true, in his Son Jesus Christ. He is the true God and eternal life.
And we know that the Son of God has come, and he has given us understanding so that we can know the true God. And now we live in fellowship with the true God because we live in fellowship with his Son, Jesus Christ. He is the only true God, and he is eternal life.