Here is what the Catechism of the Catholic Church tells us:
"The senses of Scripture
"115 According to an ancient tradition, one can distinguish between two senses of Scripture: the literal and the spiritual, the latter being subdivided into the allegorical, moral and anagogical senses. The profound concordance of the four senses guarantees all its richness to the living reading of Scripture in the Church.
"116 The literal sense is the meaning conveyed by the words of Scripture and discovered by exegesis, following the rules of sound interpretation: "All other senses of Sacred Scripture are based on the literal."83
"117 The spiritual sense. Thanks to the unity of God’s plan, not only the text of Scripture but also the realities and events about which it speaks can be signs.
"1. The allegorical sense. We can acquire a more profound understanding of events by recognizing their significance in Christ; thus the crossing of the Red Sea is a sign or type of Christ’s victory and also of Christian Baptism.84
"2. The moral sense. The events reported in Scripture ought to lead us to act justly. As St. Paul says, they were written “for our instruction”.85
"3. The anagogical sense (Greek: anagoge, “leading”). We can view realities and events in terms of their eternal significance, leading us toward our true homeland: thus the Church on earth is a sign of the heavenly Jerusalem.86
"118 A medieval couplet summarizes the significance of the four senses:
The Letter speaks of deeds; Allegory to faith;
The Moral how to act; Anagogy our destiny.87"
We cannot guess and decide for ourselves. We must investigate what the Church actually teaches. That means looking, online, for Church documents that deal with the parts of the Old Testament that some find difficult to believe.
If you read the New Testament, you see Jesus referring to the Old Testament and you will see Old Testament prophecy as given by God and statements like: “This was done so that the scripture would be fulfilled.” And similar.
bible.cc/john/19-36.htm
The Scripture John is talking about is found in the Old Testament.
Jesus read from the Old Testament in the synagogue, and said:
bible.cc/luke/4-21.htm
And then we have this statement regarding the Old Testament:
bible.cc/2_peter/1-21.htm
I also suggest the following:
amazon.com/Why-Catholic-Bibles-are-Bigger/dp/1581880103
Peace,
Ed