Heb 10:5-10, Lk 24:25-27,45-47, Jn 5:39, Acts 10:43, 1 Cor 15:3-4, 1 Pt 1:10-11
In the Old Testament, it was foretold that Christ would do what was written in the Old Testament to accomplish God's will. (Psalms 40:6-8)
Psalms 40:6 Sacrifice and offering thou didst not desire; mine ears hast thou opened: burnt offering and sin offering hast thou not required. 7 Then said I, Lo, I come: in the volume of the book it is written of me, 8 I delight to do thy will, O my God: yea, thy law is within my heart.
Jesus offered his body to God to save us, not as a sacrifice according to the Old Testament law. (Hebrews 10:5-10)
Hebrews 10:5 Wherefore when he cometh into the world, he saith, Sacrifice and offering thou wouldest not, but a body hast thou prepared me: 6 In burnt offerings and sacrifices for sin thou hast had no pleasure. 7 Then said I, Lo, I come (in the volume of the book it is written of me,) to do thy will, O God. 8 Above when he said, Sacrifice and offering and burnt offerings and offering for sin thou wouldest not, neither hadst pleasure therein; which are offered by the law; 9 Then said he, Lo, I come to do thy will, O God. He taketh away the first, that he may establish the second. 10 By the which will we are sanctified through the offering of the body of Jesus Christ once for all.
The Old Testament is the account of Christ and the record of His coming. (Luke 24:25-27,45-47, John 5:39)
Luke 24:25 Then he said unto them, O fools, and slow of heart to believe all that the prophets have spoken: 26 Ought not Christ to have suffered these things, and to enter into his glory? 27 And beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself. 45 Then opened he their understanding, that they might understand the scriptures, 46 And said unto them, Thus it is written, and thus it behooved Christ to suffer, and to rise from the dead the third day: 47 And that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem.
John 5:39 Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me.
Old Testament prophets recorded that the coming Christ would die for us and be resurrected three days later, and that all who believed in Him would have their sins forgiven. (Acts 10:43, 1 Corinthians 15:3-4, 1 Peter 1:10-11)
Acts 10:43 To him give all the prophets witness, that through his name whosoever believeth in him shall receive remission of sins.
1 Corinthians 15:3 For I delivered unto you first of all that which I also received, how 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:
1 Peter 1:10 Of which salvation the prophets have enquired and searched diligently, who prophesied of the grace that should come unto you: 11 Searching what, or what manner of time the Spirit of Christ which was in them did signify, when it testified beforehand the sufferings of Christ, and the glory that should follow.