{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.

Matthew Henry's Whole Bible Commentary

Verses 10-13

In those words we may observe,

I. The privilege and stability of the real Christian: He that believeth on the Son of God, hath been prevailed with unfeignedly to cleave to him for salvation, hath the witness in himself, v. 10. He hath not only the outward evidence that others have, but he hath in his own heart a testimony for Jesus Christ. He can allege what Christ and the truth of Christ have done for his soul and what he has seen and found in him. As, 1. He has deeply seen his sin, and guilt, and misery, and his abundant need of such a Saviour. 2. He has seen the excellency, beauty, and office of the Son of God, and the incomparable suitableness of such a Saviour to all his spiritual wants and sorrowful circumstances. 3. He sees and admires the wisdom and love of God in preparing and sending such a Saviour to deliver him from sin and hell, and to raise him to pardon, peace, and communion with God. 4. He has found and felt the power of the word and doctrine of Christ, wounding, humbling, healing, quickening, and comforting his soul. 5. He finds that the revelation of Christ, as it is the greatest discovery and demonstration of the love of God, so it is the most apt and powerful means of kindling, fomenting, and inflaming love to the holy blessed God. 6. He is born of God by the truth of Christ, as v. 1. He has a new heart and nature, a new love, disposition, and delight, and is not the man that formerly he was. 7. He finds yet such a conflict with himself, with sin, with the flesh, the world, and invisible wicked powers, as is described and provided for in the doctrine of Christ. 8. He finds such prospects and such strength afforded him by the faith of Christ, that he can despise and overcome the world, and travel on towards a better. 9. He finds what interest the Mediator has in heaven, by the audiency and prevalency of those prayers that are sent thither in his name, according to his will, and through his intercession. 10. He is begotten again to a lively hope, to a holy confidence in God, in his good-will and love, to a pleasant victory over terrors of conscience, dread of death and hell, to a comfortable prospect of life and immortality, being enriched with the earnest of the Spirit and sealed to the day of redemption. Such assurance has the gospel believer; he has a witness in himself. Christ is formed in him, and he is growing up to the fulness and perfection, or perfect image of Christ, in heaven.

II. The aggravation of the unbeliever's sin, the sin of unbelief: He that believeth not God hath made him a liar. He does, in effect, give God the lie, because he believeth not the record that God gave of his Son, v. 10. He must believe that God did not send his Son into the world, when he has given us such manifold evidence that he did, or that Jesus Christ was not the Son of God, when all that evidence relates to and terminates upon him, or that he sent his Son to deceive the world and to lead it into error and misery, or that he permits men to devise a religion which, in all the parts of it, is a pure, holy, heavenly, undefiled institution, and so worthy to be embraced by the reason of mankind, and yet is but a delusion and a lie, and then lends them his Spirit and power to recommend and obtrude it upon the world, which is to make God the Father, the author and abettor, of the lie.

III. The matter, the substance, or contents of all this divine testimony concerning Jesus Christ: And this is the record, that God hath given to us eternal life, and this life is in his Son, v. 11. This is the sum of the gospel. This is the sum and epitome of the whole record given us by all the aforesaid six witnesses. 1. That God hath given to us eternal life. He has designed it for us in his eternal purpose. He has prepared all the means that are necessary to bring us to it. He has made it over to us by his covenant and promise. And he actually confers a right and title thereto on all who believe on and actually embrace the Son of God. Then, 2. This life is in the Son. The Son is life; eternal life in his own essence and person, Jn. 1:4; 1 Jn. 1:2. He is eternal life to us, the spring of our spiritual and glorious life, Col. 3:4. From him life is communicated to us, both here in heaven. And thereupon it must follow, (1.) He that hath the Son hath life, v. 12. He that is united to the Son is united to life. He who hath a title to the Son hath a title to life, to eternal life. Such honour hath the Father put upon the Son: such honour must we put upon him too. We must come and kiss the Son, and we shall have life. (2.) He that hath not the Son of God hath not life, v. 12. He continues under the condemnation of the law (Jn. 3:36); he refuses the Son, who is life itself, who is the procurer of life, and the way to it; he provokes God to deliver him over to endless death for making him a liar, since he believes not this record that God hath given concerning his Son.

IV. The end and reason of the apostle's preaching this to believers. 1. For their satisfaction and comfort: These things have I written unto you that believe on the name of the Son of God, that you may know that you have eternal life, v. 13. Upon all this evidence, and these witnesses, it is but just and meet that there should be those who believe on the name of the Son of God. God increase their number! How much testimony from heaven has the world to answer for! And to three witnesses in heaven must the world be accountable. These believers have eternal life. They have it in the covenant of the gospel, in the beginning and first-fruits of it within them, and in their Lord and head in heaven. These believers may come to know that they have eternal life, and should be quickened, encouraged, and comforted, in the prospect of it: and they should value the scriptures, which are so much written for their consolation and salvation. 2. For their confirmation and progress in their holy faith: And that you may believe on the name of the Son of God (v. 13), may go on believing. Believers must persevere, or they do nothing. To withdraw from believing on the name of the Son of God is to renounce eternal life, and draw back unto perdition. Therefore the evidences of religion and the advantage of faith are to be presented to believers, in order to hearten and encourage them to persevere to the end.