But we have more. We have the entire OT (not to mention nature and all that's metaphysical). The OT tells the story of Jesus pre-kenosis - or pre-humility into humanity.
To the Jews Jesus had riled up after claiming equality with God Jesus said, 'You search the Scriptures because you think that in them you have eternal life; it is these that testify about Me' John 5:39.
They believed eternal life was found in strict adherence to the Law. The Torah. And yet Jesus was turning the page on their beliefs. The very Law that they believed led to life actually pointed to Jesus. Let's get mystical, mystical (Olivia Newton John anyone?) - think of it like this, the Jews were merely looking at the Scriptures to stave off death when they should have been looking through the Scriptures to see His Life. The Sciptures point to the Living Word, the Son of God, the very Man standing before them - Christ.
Jesus simply told them to search the Scriptures and they'd find Him. OK:
Isaiah 7:14 - Jesus' birth - Matthew 1:23
Psalm 16:10 - Resurrection - Acts 2:31
Zechariah 11:12-13 - Price for Jesus' life - Matthew 26:15, 27:5,7
Genesis 49:10 - From the Tribe of Judah - Hebrews 7:14
Isaiah 61:1-2 - Holy Spirit on Him - Luke 4:15-21
Maybe it's not so mystical. We know that Scripture is God-breathed, that it's living and active and that it's to be handled with the utmost care. Maybe it's simply a matter of prayer, study, belief and Sprit. Supernatural, but maybe not mystical.
There are hundreds more examples. Entire passages, stories and characters such as: the Exodus, Temple, Jonah, Hosea, Babylonian Captivity etc. and all tell pieces of the story of the eternal life of Christ.
Since Scriptures origin is also the author of the universe (2 Peter 1:20-21), it stands to reason that when Jesus claimed to be the true life found within the Scriptures...he wasn't insane, lying nor exaggerating - He was providing authentic testimony to His own being.