These things I have 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. (1 John 5:13)
This verse is often cited in favour of the doctrine of eternal security; often, Evangelicals who hold to some variation of this doctrine will claim that Latter-day Saints are incorrect in claiming that a justified person can lose their salvation through the commission of heinous sins (cf. D&C 20:32).
Firstly, it should be noted that this doctrine is refuted by any meaningful exegesis of many texts from the Bible, such as Heb 6:4-6 and 10:26.
Secondly, this is a classic example of absolutizing a verse and ignoring its overall context. A parallel can be the use of John 17:3 by some groups to preclude the divinity of Jesus Christ (e.g., Jehovah’s Witnesses; Christadelphians). Indeed, when one examines the context of this verse, it refutes, not supports, the eisegesis of many Evangelical groups. Indeed, the context of this verse is a series of tests and questions from the author of this Epistle to the recipients, showing that the confidence one has is subjective, not objective:
Whosoever believeth that Jesus is the Christ is born of God: and every one that loveth him that begat loveth him also that is begotten of him. By this we know that we love the children of God, when we love God, and keep his commandments. For this is the love of God, that we keep his commandments: and his commandments are not grievous. For whatsoever is born of God overcometh the world: and this is the victory that overcometh the word, even our faith. Who is he that overcometh the world, but he that believeth that Jesus is the Son of God? This is he that came by water and blood, even Jesus Christ; not by water only, but by water and blood. And it is the Spirit that beareth witness, because the Spirit is truth . . . And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one. If we receive the witness of men, the witness of God is greater: for this is the witness of God which he hath testified of his Son. He that believeth on the Son of God hath the witness in himself: he that believeth not God hath made him a liar; because he believeth not the record that God gave of his Son. He that hath the Son hath life; and he that hath not the Son of God hath not life. (1 John 5:1-6, 8-12 [v. 7, the infamous Comma Johanneum, omitted, as it is a later, spurious insertion into the text]).
Thirdly, 1 John contains warnings to believers that they can fall away from the faith:
Who is a liar but he that denieth that Jesus is the Christ? He is the antichrist, that denieth the Father and the Son. Whosoever denieth the Son, the same hath not the Father: (but) he that acknowledgeth the Son hath the Father also. Let that therefore abide in you, which ye have heard from the beginning. If that which ye have heard from the beginning shall remain in you, ye also shall continue in the Son, and in the Father. And this is the promise that he hath promise us, even eternal life. These things have I written unto you concerning them that seduce you.(2:22-26)
And now, little children, abide in him; that, when he shall appear, we may have confidence, and not be ashamed before him at his coming. (2:28)
In many other texts, the inspired authors spoke of confidence, but not infallible assurance, of their salvation and/or the salvation of others. Paul in 2 Tim 1:16-18, speaking of the recently deceased Christian, Onesiphorus, wrote the following:
The Lord give mercy unto the house of Onesiphorus; for he oft refreshed me, and was not ashamed of my chain: But, when he was in Rome, he sought me out very diligently, and found me. The Lord grant unto him that may find mercy of the Lord in that day: and in how many things he ministered unto me at Ephesus, thou knowest very well.
Onesiphorus was a great man who, in two cities, was right by Paul's side. It is Paul's desire that Onesiphorus find mercy from God on the day of final judgment. The phrase, "The Lord grant unto him" in v. 18 translates the term δῴη αὐτῷ ὁ κύριος; δῴη is the aorist optative of διδωμι, "to give." Many translations (correctly) render it as "may the Lord grant him" (e.g., NRSV; ESV; NIV; NJB), showing that Paul is not stating absolutely that Onesiphorus will find mercy, which entails the full pardon of sin and overlooking of faults. While Onesiphorus will find mercy at the last day, the point is that he (and all of us) will have to wait until the final day for the complete mercy of God to be applied to him. Indeed, this is the very same Paul who spoke of the possibility that he would lose his salvation and become a reprobate (1 Cor 9:27; cf 1 Cor 4:4-5).
New Testament scholar I. Howard Marshall, when summarising the soteriology in 1 John, was spot-on when he wrote:
As might be expected, John affirms strongly here also the doctrine of perseverance. A man born of God and kept by Him cannot sin (1 John 3:9, 5:18), and can overcome the world. At the same time, his progress to final salvation is not automatic. For example, although John teaches that all believers through their possession of the Spirit have knowledge (1 John 2:20), it is still necessary for him to give them plentiful admonition and teaching. He has to urge them to keep the commandments of God (1 John 2:7) and to abide in Jesus (1 John 2:28; cf. also 1 John 2:15, 24, 27; 3:3, 18; 5:21; 2 John 7-11). He knows that they can and do fall into sin. (I. Howard Marshall, Kept by the Power of God: A Study of Perseverance and Falling Away [Minneapolis, Minn.: Bethany Fellowship, Inc., 1969], 186, emphasis added)
As we have seen, the common appeal to 1 John 5:13 to “prove” eternal security is proven to be another example of eisegesis.