The study of types and antitypes of Biblical Characters, theology, history, events and statements in the Bible is called Typology. The whole purpose of the Old Testament is viewed as the provision of types for Christ and the fulfilment of the Law.
The most famous types in the bible are the parallel stories of Joseph and Jesus. Both rejected by their Jewish brothers who became the bread of life to the Gentile world, who will one day return for his Jewish brothers.
Typology also teaches us object lessons from the Bible. For instance, the Tree of Knowledge of Good and Evil is equated to the Ten Commandments and the Tree of Life is equated to Christ’s works on the Cross. Typology, in this case, teaches us the effects of being under the Tree of Knowledge of Good and Evil versus being under the Tree of Life.
Paul used typology extensively in his letters
He used the Old Testament to preach truths of the New Covenant. He revealed Jesus and His finished works on the cross from the shadows of the Old Testament.
Tell me, you who desire to be under the law, do you not hear the law? For it is written that Abraham had two sons: the one by a bondwoman, the other by a freewoman. But he who was of the bondwoman was born according to the flesh, and he of the freewoman through promise, which things are symbolic. For these are the two covenants: the one from Mount Sinai which gives birth to bondage, which is Hagar— for this Hagar is Mount Sinai in Arabia, and corresponds to Jerusalem which now is, and is in bondage with her children— but the Jerusalem above is free, which is the mother of us all.
~ Galatians 4:21-26
Paul equates the Law (Ten Commandments) to Hagar because the Ten Commandments were given to Moses on Mount Sinai. And Paul equates Grace to Sarah because the Holy Spirit was revealed for the first time on mount Zion in Jerusalem.
With this typology, we can go deeper in understanding the quick but temporary effects of the Ten Commandments and the seemingly slow but permanent effects of Grace.
Sarah thought God’s promise that she would bear a Son was not enough. She wanted to be practical, so she ordered Abraham to sleep with the servant girl (Hagar).
Sarah and Abraham tried to have a child for years, but were old and still without a child. They got tired of waiting and Abraham decided to sleep with the servant girl ONLY ONCE and Ishmael was born. That was quick.
So the result of preaching the Ten Commandments causes there to be a quick outward result of morality. Whereas Grace seems impractical.
But to what end?
Ishmael was such a pain to Sarah that she couldn’t stand him. As will be the result of preaching the Ten Commandments. The quick results of outward morality are only temporary. Sarah was so frustrated with Ishmael that she said, “Cast out the bondwoman and her son”. So we must also cast out the Ten Commandments, seeing it nailed to Jesus on the cross.
Now we, brethren, as Isaac was, are children of promise. But, as he who was born according to the flesh then persecuted him who was born according to the Spirit, even so it is now. Nevertheless what does the Scripture say? “Cast out the bondwoman and her son, for the son of the bondwoman shall not be heir with the son of the freewoman.” So then, brethren, we are not children of the bondwoman but of the free.
~ Galatians 4: 28-31
Overall, Biblical Typology helps believers in many ways. It offers a clear connection between Old and New Testaments, reveals the unity of the Bible, and emphasizes the New Covenant believers experience in the finished work of Jesus Christ.
An understanding of Biblical Typology can help inspire and motivate our faith as we see how God has worked throughout history in profound ways that continue to impact our lives.