1 Corinthians 15:3-4, For I handed down to you all in the first place what I also received: that Christ died for our sins according to the Scriptures; and that He was buried and that He has risen on the third day according to the Scriptures. (Own Greek translation.)
This tradition has been passed down to us: the teaching that Christ died for our sins, was buried, and rose from the dead on the third day, according to the Scriptures—that is, the Hebrew Scriptures. Our Scriptures are the Old and New Testaments. The Scriptures of the apostles, however, were the Old Testament—better called the Torah, Prophets, and Writings. Where is this confession written? Isaiah 53, particularly verse 10, “Yet it was the will of the LORD to crush him [cf. Gen. 3:15]; He has put him to grief; when his soul makes an offering for guilt, he shall see his offspring; He shall prolong his days; the will of the LORD shall prosper in his hand.”
Thus, we can trust the witness of the apostles because the Hebrew Scriptures testified first of Christ, His atoning sacrifice (Christus vicar), and His resurrection (Christus victor, “He shall prolong his days”). We continue this testimony that has been passed down to us through the ages. The apostles were eyewitnesses of the testimony of the Hebrew Scriptures, and they have passed down their eyewitness testimonies to the Church. And now, we wait for and testify the second coming of our Lord, after which we shall live as witnesses in the New Jerusalem.