By which—ye are saved.— "By which you are brought into a state of salvation; into the way of being completely and eternally saved." The next clause should be rendered, If you retain those joyful tidings which I delivered unto you. The words rendered unless, εκτος ει μη, are remarkable, and may suggest the thought expressed 1 Corinthians 15:17. So the first two verses may be a transition; as if he had said, "I preach the same gospel still, and I hope you will retain it: yet I have reason to fear that some of you entertain notions which tend quite to enervate it." Some would render εκτος ει μη with a comma, making it an exception to the former clause,—but if not,—if you do not retain what I have preached,—you have believed in vain. See 1 Timothy 5:19.
Related Commentaries of 1 Corinthians 15:2
1 Corinthians 15:2
2 By which also ye are saved, if ye keepa in memory what I preached unto you, unless ye have believed in vain.