Jesus taught the entire Old Testament, not just a few passages that mention the Messiah.
Jesus said that the entire Old Testament speaks of him.
More specifically, it states that it records the suffering and resurrection of Christ and that the gospel will be preached to all nations.
Therefore, the Old Testament is a book that shows the gospel of Jesus Christ in every single page.

---From "Introduction to the Old Testament"

Adam, God's first son, failed to rebuke the serpent, but the promised son will rebuke the serpent.
Also, Adam failed to crush the serpent's head by standing naked next to a tree, but the promised son will run naked to a tree and eventually crush the serpent's head.
By doing so, the promised son, the offspring of the woman, will restore all that the first son had lost.

---From "Chapter 1 Genesis 1"

The image of God passing alone between the pieces of the sacrifice (Genesis 15:17) clearly shows that the fulfillment of the covenant belongs only to God.
This is a sign that God will keep the covenant he made with mankind.
The only way to make this sign more vivid is to put symbolic actions into practice.
The eternally living God took on human flesh and tasted death in place of Adam's descendants who broke the covenant.
This is what God did through Christ.

---From "Chapter 2 Genesis 2"

The concept of God's presence first appears in God's redemptive history.
God has never dwelt among people.
Even in the Garden of Eden, God visited Adam and Eve periodically, but did not live with them.
But from this time on, God became ‘Immanuel,’ ‘God with us.’
---From "Chapter 3 Exodus"

According to the Old Testament feast regulations, Jesus Christ was resurrected on the first Sabbath after Passover and became the first fruit of the resurrection.
And 50 days later, on the day of Pentecost, the Holy Spirit came, announcing the harvest of the kingdom of God.
Although the beginning of the harvest (Passover and the Feast of Unleavened Bread) is clearly connected to the completion of the harvest (the Feast of Weeks), they are separated in time.
Likewise, the resurrection of Christ is a sure sign foreshadowing the final harvest, but there is a clear lag between the resurrection of Christ and the resurrection of his people.

---From Chapter 4, Leviticus

Like the Israelites, we too are in the wilderness.
The many trials we face in life can be compared to the trials the Israelites faced in the wilderness.
You can see this in Hebrews chapter 3.
The two generations who lived in the wilderness show two different lives.
We can, like the first generation, complain and blame God when life throws us into trouble, or, like the second generation, we can look forward to tomorrow with the strength God gives us.
No matter which path we choose, God's promises will surely come true.
God prepares his people to fulfill his promises and gives them an inheritance.

---From Chapter 5, Numbers

Whether it was when the Law covenant was first made with Israel at Mount Sinai, or later when it was made again with the wilderness generation, the biggest problem was in Israel's heart.
Do you remember what God said to them in Deuteronomy 10:16? "Circumcise your heart." But who is performing the circumcision in chapter 30:6? It's God.
God is getting to the heart of the matter.
Because the heart of the problem lies in the human mind.

---From "Chapter 6, Deuteronomy"

In the end, Joshua conquered the entire land of Canaan, just as the Lord had commanded Moses, and divided it among the tribes, allowing them to enjoy the land's produce.
And then finally there was peace in the land (Joshua 11:23).
The Israelites enjoyed rest, and the conclusion seems to be, “They all lived happily ever after.”
But the Bible story doesn't end here.

---From "Chapter 7 Joshua"