There are three witnesses, the Spirit, the water, and the blood; and these three agree.
If we receive the testimony of men, the testimony of God is greater; for this is the testimony of God that he has borne witness to his Son.
He who believes in the Son of God has the testimony in himself. He who does not believe God has made him a liar, because he has not believed in the testimony that God has borne to his Son.
And this is the testimony, that God gave us eternal life, and this life is in his Son.
He who has the Son has life; he who has not the Son of God has not life.
I write this to you who believe in the name of the Son of God, that you may know that you have eternal life.
And this is the confidence which we have in him, that if we ask anything according to his will he hears us.
And if we know that he hears us in whatever we ask, we know that we have obtained the requests made of him.
If any one sees his brother committing what is not a mortal sin, he will ask, and God will give him life for those whose sin is not mortal. There is sin which is mortal; I do not say that one is to pray for that.
All wrongdoing is sin, but there is sin which is not mortal.
We know that any one born of God does not sin, but He who was born of God keeps him, and the evil one does not touch him.
Revised Standard Version of the Bible, copyright 1952 [2nd edition, 1971] by the Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved. (Revised Standard Version - Holy Bible)