1 Corinthians 15:1-4 says:

Now I make known to you, brethren, the gospel which I preached to you, which also you received, in which also you stand, ²by which also you are saved, if you hold fast the word which I preached to you, unless you believed in vain. ³For I delivered to you as of first importance what I also received, that Christ died for our sins according to the Scriptures, ⁴and that He was buried, and that He was raised on the third day according to the Scriptures... 1 Corinthians 15:1-4 (NAS)

Question:

According to I Corinthians 15:1-2, the gospel had been preached to them. They had received it and were standing firm in it. They would be saved by it if they did what?

Other Translations - 1 Corinthians 15:1-4:

Now, brothers, I want to remind you of the gospel I preached to you, which you received and on which you have taken your stand. By this gospel you are saved, if you hold firmly to the word I preached to you. Otherwise, you have believed in vain. For what I received I passed on to you as of first importance: that Christ died for our sins according to the Scriptures, that he was buried, that he was raised on the third day according to the Scriptures, (NIV)

Moreover, brethren, I declare to you the gospel which I preached to you, which also you received and in which you stand,by which also you are saved, if you hold fast that word which I preached to you-- unless you believed in vain. For I delivered to you first of all that which I also received: that Christ died for our sins according to the Scriptures, and that He was buried, and that He rose again the third day according to the Scriptures, (NKJ)

Now I make known unto you brethren, the gospel which I preached unto you, which also ye received, wherein also ye stand,by which also ye are saved, if ye hold fast the word which I preached unto you, except ye believed in vain. For I delivered unto you first of all that which also I received: that Christ died for our sins according to the scriptures; and that he was buried; and that he hath been raised on the third day according to the scriptures; (ASV)

Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand; By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; And that he was buried, and that he rose again the third day according to the scriptures: (KJV)

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