NET

20 And we know that the Son of God has come and has given us insight to know him who is true, and we are in him who is true, in his Son Jesus Christ. This one is the true God and eternal life.

Darby

20 And we know that the Son of God has come, and has given us an understanding that we should know him that [is] true; and we are in him that [is] true, in his Son Jesus Christ. He is the true God and eternal life.

KJV

20 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.