By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain.

by which also ye are saved, if ye hold fast the word which I preached unto you, except ye believed in vain.

by which also ye are saved, (if ye hold fast the word which I announced to you as the glad tidings,) unless indeed ye have believed in vain.

by which also ye are saved; I make known, I say, in what words I preached it unto you, if ye hold it fast, except ye believed in vain.

through which also ye are being saved, in what words I proclaimed good news to you, if ye hold fast, except ye did believe in vain,

through which also you are obtaining salvation, if you bear in mind the words in which I proclaimed it - unless indeed your faith has been unreal from the very first.

By which you have salvation; that is to say, the form in which it was given to you, if it is fixed in your minds, and if your faith in it is not without effect.

By the Gospel, too, you are being saved, if you hold to the understanding that I preached to you, lest you believe in vain.

and by means of which you are being saved. I would like to remind you of the words that I used in telling it to you, since you are still holding fast to it, and since it was not in vain that you became believers in Christ.

If you keep in memory -- unless in vain [1] These two expressions are very cutting. In the first, he reproves their carelessness or fickleness, because such a sudden fall was an evidence that they had never understood what had been delivered to them, or that their knowledge of it had been loose and floating, inasmuch as it had so quickly vanished. By the second, he warns them that they had needlessly and uselessly professed allegiance to Christ, if they did not hold fast this main doctrine. [2]

Footnotes

1 - "Our version does not express intelligibly the sense of ektos ei me eiko episteusate by rendering it so literally -- unless ye have believed in vain. To believe in vain, according to the use of ancient languages, is to believe without just reason and authority, giving credit to idle reports as true and authentic. Thus Plutarch, speaking of some story which passed current, says, touto hemeis e'ipomen en ti ton eiko pepisteumenon -- "this I said was one of those tales which are believed without any good authority." (Sympos. lib. 1, quaest. 6.) The Latins used credere frustra -- to believe in vain, or temere -- (rashly.) Kypke takes notice that ektos ei me, for except or unless, which has long been a suspected phrase, is used more than ten times by Lucian. It is also used by Plutarch in the Life of Demosthenes, volume 4." -- Alexander's Paraphrase on 1-Corinthians 15. (London, 1766,) -- Ed.

2 - "Ce principal poinct de la foy;" -- "This main article of faith."

By which also ye are saved - On which your salvation depends; the belief of which is indispensable to your salvation; see the note on Mark 16:16. The apostle thus shows the "importance" of the doctrine. In every respect it demanded their attention. It was that which was first preached among them; that which they had solemnly professed; that by which they had been built up; and that which was connected with their salvation. It does not mean simply that by this they were brought into a salvable state (Clarke, Macknight, Whitby, Bloomfield, etc.), but it means that their hopes of eternal life rested on this; and by this they were then "in fact" saved from the condemnation of sin, and were in the possession of the hope of eternal life.
If ye keep in memory - Margin, as in the Greek, "if ye hold fast." The idea is, that they were saved by this, or would be, if they faithfully retained or held the doctrine as he delivered it; if they observed it, and still believed it, notwithstanding all the efforts of their enemies, and all the arts of false teaching to wrest it from them. There is a doubt delicately suggested here, whether they did in fact still adhere to his doctrine, or whether they had not abandoned it in part for the opposite.
Unless ye have believed in vain - You will be saved by it, if you adhere to it, unless it shall turn out that it was vain to believe, and that the doctrine was false. That it was "not" false, he proceeds to demonstrate. Unless all your trials, discouragements, and hopes were to no purpose, and all have been the result of imposture; and unless all your profession is false and hollow, you will be saved by this great doctrine which I first preached to you.

By which also ye are saved - That is, ye are now in a salvable state; and are saved from your Gentilism, and from your former sins.
If ye keep in memory - Your future salvation, or being brought finally to glory, will now depend on your faithfulness to the grace that ye have received.

By which also ye are saved, if ye keep in memory what I preached unto you, (b) unless ye have believed in vain.
(b) Which is very absurd, and cannot be, for they that believe must reap the fruit of faith.

By which also ye are saved,.... It was the means of their salvation, and had been made the power of God unto salvation to them. Salvation is inseparably connected with true faith in Christ as a Saviour, and with a hearty belief of his resurrection from the dead, which is the earnest and pledge of the resurrection of the saints; and because of the certainty of it in the promise of God, through the obedience and death of Christ, and in the faith and hope of believers, which are sure and certain things, they are said to be saved already. To which the apostle puts in the following provisos and exceptions; the one is,
if ye keep in memory what I preached unto you; or rather, "if ye hold fast, or retain"; that is, by faith, the doctrine preached to you, and received by you, particularly the doctrine of the resurrection of the dead; for the salvation that is connected with it does not depend upon the strength of the memory, but upon the truth and steadfastness of faith: it is the man that perseveres in the faith and doctrine of Christ that shall be saved; and everyone that has truly believed in Christ, and cordially embraced his Gospel, shall hold on, and out to the end; though the faith of nominal believers may be overthrown by such men, as Hymenaeus and Philetus, who asserted, that the resurrection was past already; but so shall not the faith of real believers, because the foundation on which they are built stands sure, and the Lord has perfect knowledge of them, and will keep and save them. The other exception is,
unless ye have believed in vain: not that true faith can be in vain; for that is the faith of God's elect, the gift of his grace, the operation of his Spirit; Christ is the author and finisher of it, and will never suffer it to fail; it will certainly issue in everlasting salvation: but then as the word may be heard in vain, as it is by such who are compared to the wayside, and to the thorny and rocky ground; and as the Gospel of the grace of God may be received in vain; so a mere historical faith may be in vain; this a man may have, and not the grace of God, and so be nothing; with this he may believe for a while, and then drop it: and since each of these might possibly be the case of some in this church, the apostle puts in these exceptions, in order to awaken the attention of them all to this important doctrine he was reminding them of.

ye are saved--rather, "ye are being saved."
if ye keep in memory what I preached unto you--Able critics, BENGEL and others, prefer connecting the words thus, "I declare unto you the Gospel (1-Corinthians 15:1) in what words I preached it unto you." Paul reminds them, or rather makes known to them, as if anew, not only the fact of the Gospel, but also with what words, and by what arguments, he preached it to them. Translate in that case, "if ye hold it fast." I prefer arranging as English Version, "By which ye are saved, if ye hold fast (in memory and personal appropriation) with what speech I preached it unto you."
unless--which is impossible, your faith is vain, in resting on Christ's resurrection as an objective reality.

Ye are saved, if ye hold fast - Your salvation is begun, and will be perfected, if ye continue in the faith. Unless ye have believed in vain - Unless indeed your faith was only a delusion.