1 Corinthians 15
1 Moreover, brethren, I declare to you the gospel which I preached to you, which also you received and in which you stand,
2 by which also you are saved, if you hold fast that word which I preached to you - unless you believed in vain.
3 For I delivered to you first of all that which I also received: that Christ died for our sins according to the Scriptures,
4 and that He was buried, and that He rose again the third day according to the Scriptures,
5 and that He was seen by Cephas, then by the twelve.
6 After that He was seen by over five hundred brethren at once, of whom the greater part remain to the present, but some have fallen asleep.
7 After that He was seen by James, then by all the apostles.
8 Then last of all He was seen by me also, as by one born out of due time.
9 For I am the least of the apostles, who am not worthy to be called an apostle, because I persecuted the church of God.
10 But by the grace of God I am what I am, and His grace toward me was not in vain; but I labored more abundantly than they all, yet not I, but the grace of God which was with me.
11 Therefore, whether it was I or they, so we preach and so you believed.
What is believing in vain ... or grace from God that would be in vain in this passage?
Also, in verse 2, there is an "if" that makes the salvation being spoken of sound conditional upon continuing to "hold fast to the word," but maybe there is a better rendering of the verse that I have not seen just yet.
Does anyone have any thoughts on these ponderings?