By what principle of interpretation does Paul say, ‘Which things are an allegory’? Is he justified in treating a historical passage in this way? After all, what we must understand by these words is nothing less than that these details of Abraham’s family life and his personal history should be seen as illustrative of fundamental spiritual truths, and that God always intended it to be so. Paul cannot simply mean that, in looking around for a suitable illustration, he noted that he could use the circumstances of Abraham’s life for his purpose, as if this was his own idea and not a lesson designed by God. He does not say that these things can be used as an allegory, but, ‘which things are an allegory’. Types are a teaching method of the Lord; they teach us about heavenly things in terms of earthly things. What this implies is that although Genesis is truly historical and the events recorded literally took place, God was at the same time directing those events with supernatural skill in order to construct a message on the canvas of history that would contain lessons for all mankind. Only God could do such a thing. We must not for a moment forget that these things literally happened. Paul is not saying that what Moses wrote is not history but allegory, and that for years his words have been misinterpreted. The point being made is far more wonderful than that. If Moses had written only allegorical stories, then he could still have taught us the same theological lessons, but they would have had no divine authority. When however they are locked into the pages of history they are self-authenticated for they come in a form which only God is capable of giving.
Admitting that the Old Testament contains types and figures, how do we know what is and what is not a type and avoid allegorizing the entire Bible? Calvin warns: ‘But as the apostle declares that these things are allegorized, Origen, and many others along with him, have seized the occasion of torturing Scripture in every possible manner away from the true sense.’ One answer is to say that the only types which may be accepted are those which the New Testament identifies. But if we must wait for the New Testament to tell us which passages are typical or allegorical, how could Scripture have been interpreted before the New Testament was written? Paul says, ‘Do you not hear the law?’ and his question indicates that he expects the Galatians to have understood this lesson without his help. God is the instructor of the world and it is one of his teaching methods to set up types; and all legitimate types in Scripture are earthly symbols representing realities found in Christ’s kingdom. There is a natural correspondence between a type and what it represents, its antitype, which invites the human mind to make comparisons and find instruction from both similarities and dissimilarities (Romans 5:14-15). Scripture provides several rich seams of types based on the divine intention to make one thing a picture of another. Creation itself is one such seam, for the physical creation is in many respects an analogue of the new creation. Another is the typical side of the Abrahamic covenant including his natural descendants, the land promised to them, their history as a nation, all of which have their counterpart in the evangelical side of that covenant, made with the children of promise. Yet another seam is the ceremonial law which Hebrews tells us was given to be a shadow to good things to come (Hebrews 8:5; 10:1). This includes both typical objects – notably the temple itself, as well as the rituals God commanded to be performed in connection with Old Testament worship. Various individuals from each of these seams are types, especially those that stand at the head of some divine arrangement. Some relate to Christ – the first Adam is a picture of the second Adam; the mediator of the old covenant is a type of the mediator of the new covenant; the first priest is a type of our heavenly Priest, the first approved king is a type of the King of heaven. Others relate to elements of his kingdom – Hagar representing those under the law who are shut out, and Sarah representing those who are under grace and are saved. Types are like the elements of a parable which have significance, but instead of coming from a story, they come from real life. There must be a clear correspondence between the type and the antitype, which means that the connection between the type and its antitype involve significant features of each and not just incidental features.