by which also you are saved, if you hold fast the word which I preached to you, unless you believed in vain.

But by the grace of God I am what I am, and His grace toward me did not prove vain; but I labored even more than all of them, yet not I, but the grace of God with me.

and if Christ has not been raised, then our preaching is vain, your faith also is vain.

Therefore, my beloved brethren, be steadfast, immovable, always abounding in the work of the Lord, knowing that your toil is not in vain in the Lord.