{13} 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.

(13) The conclusion of the epistle, in which he shows first of all, that even they who already believe, need this doctrine, that they may grow more and more in faith: that is to say, that they may be daily more and more certain of their salvation in Christ, through faith.

People's New Testament

5:13 These things have I written unto you. He writes that they may understand how they may know that they have eternal life. Tests have been given. For example, see 1Jo 5:1,2 4:13.

That ye may believe on the name of the Son of God. Put the fullest trust in the name of Christ.

Wesley's Notes

5:13 These things have I written - In the introduction, 1John 1:4, he said, I write: now, in the close, I have written. That ye may know - With a fuller and stronger assurance, that ye have eternal life.

Jamieson-Fausset-Brown Bible Commentary

13. The oldest manuscripts and versions read, "These things have I written unto you [omitting 'that believe on the name of the Son of God'] that ye may know that ye have eternal life (compare 1Jo 5:11), THOSE (of you I mean) WHO believe (not as English Version reads, 'and that ye may believe') on the name of the Son of God." English Version, in the latter clause, will mean, "that ye may continue to believe," &c. (compare 1Jo 5:12).

These things-This Epistle. He, towards the close of his Gospel (Joh 20:30, 31), wrote similarly, stating his purpose in having written. In 1Jo 1:4 he states the object of his writing this Epistle to be, "that your joy may be full." To "know that we have eternal life" is the sure way to "joy in God."

Matthew Henry's Concise Commentary

5:13-17 Upon all this evidence, it is but right that we believe on the name of the Son of God. Believers have eternal life in the covenant of the gospel. Then let us thankfully receive the record of Scripture. Always abounding in the work of the Lord, knowing that our labour is not in vain in the Lord. The Lord Christ invites us to come to him in all circumstances, with our supplications and requests, notwithstanding the sin that besets us. Our prayers must always be offered in submission to the will of God. In some things they are speedily answered; in others they are granted in the best manner, though not as requested. We ought to pray for others, as well as for ourselves. There are sins that war against spiritual life in the soul, and the life above. We cannot pray that the sins of the impenitent and unbelieving should, while they are such, be forgiven them; or that mercy, which supposes the forgiveness of sins, should be granted to them, while they wilfully continue such. But we may pray for their repentance, for their being enriched with faith in Christ, and thereupon for all other saving mercies. We should pray for others, as well as for ourselves, beseeching the Lord to pardon and recover the fallen, as well as to relieve the tempted and afflicted. And let us be truly thankful that no sin, of which any one truly repents, is unto death.