1 John 5:7
For there are three that bear record in heaven,
the Father, the Word, and the Holy Ghost:
and these three are one.

1 John 5:11-12
And this is the record,
that God hath given to us eternal life,
and this life is in his Son.
He that hath the Son hath life;
and
he that hath not the Son of God hath not life.


From:

Samuel Mather
http://www.purebibleforum.com/showth...-Samuel-Mather


p. 7 has a superb internal argument
https://books.google.com/books?id=Rp5bAAAAQAAJ&pg=PA7


What is declared is very plain, 1 John v. 11, 12.
this is the Record.
that God hath given to us eternal Life,
and this Life is in his Son;
he that hath the Son hath Life,
and he that hath not the Son of God,
hath not Life.

These Words evidently imply, that the Apostle had before declared, that God had given a Record or Witness, It is plain, I John v. 7. There are three that hear Record (or Witness,) in Heaven, and these three are one. In the 7th Verse, he declares what the Record was, which the Father, Word and Holy Ghoft bore.

We may as well reject all the Chapter, as the 7th verse.
And by a like Course of Management, cast off the Authority of the three Epistles, and Gospel of this Apostle. A compendious Way to finish a Debate ! But unless we do thus, the Place must necessarily remain as we have it; which an ingenious Gentleman has shewn in two Letters to Dr. Bently. And it’s a better Argument, to prove the Genuiness of the 7th Verse, than they who are otherwise minded, can produce in Favour of their Opinion. I shall hereafter resume the Question, relating to the Truth of the Text, as opposed to Interpolation.