1 Cor. 15, 1-10.
But I remind you, brethren, of the gospel which I preached to you, which you also received, in which also you stand, by which also you are saved, in which form I preached it to you, if you kept it, unless you believed it in vain. For I have given 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; and that he was seen of Cephas, and after that of the twelve; and after that he was seen of more than five hundred brethren at once, many of whom are yet alive, but some have fallen asleep. Then he was seen by Jacob, then by all the apostles, and last of all by me, who was born prematurely. For I am the least of the apostles, as I am not worthy to be called an apostle, because I have persecuted the church of God. But by the grace of God I am what I am, and His grace toward me has not been in vain; but I have labored much more than they all; not I, but the grace of God which is with me.
This epistle is abundantly interpreted in the sermons on this whole chapter, especially in the past; whoever wants to, may read it there. It speaks entirely of the resurrection of the dead, which is why it should be read and acted upon around Easter. But the fact that it was arranged for this Sunday seems to be due to the fact that the last part rhymes with the Gospel of this Sunday: St. John the Baptist is the first to say this.
Paul, though he was a high apostle, and had labored more in his ministry than all the rest; yet he does not boast of his own work, like the hopeful Pharisee, but, like the poor publican, confesses his sin and unworthiness, and what he is, ascribes to God's grace alone, who, being a persecutor, made him a Christian and an apostle.