Passage cross-references.

This is the disciple which testifieth of these things, and wrote these things: and we know that his testimony is true.

And ye also shall bear witness, because ye have been with me from the beginning.

How shall we escape, if we neglect so great salvation; which at the first began to be spoken by the Lord, and was confirmed unto us by them that heard him; …

That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled, of the Word of life; …

But these are written, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name.

And we are witnesses of all things which he did both in the land of the Jews, and in Jerusalem; whom they slew and hanged on a tree:

For whatsoever things were written aforetime were written for our learning, that we through patience and comfort of the scriptures might have hope.

The elders which are among you I exhort, who am also an elder, and a witness of the sufferings of Christ, and also a partaker of the glory that shall be revealed:

And I am glad for your sakes that I was not there, to the intent ye may believe; nevertheless let us go unto him.

And I knew that thou hearest me always: but because of the people which stand by I said it, that they may believe that thou hast sent me.

And now I have told you before it come to pass, that, when it is come to pass, ye might believe.

Neither pray I for these alone, but for them also which shall believe on me through their word; …

When Jesus therefore saw his mother, and the disciple standing by, whom he loved, he saith unto his mother, Woman, behold thy son!

These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God.