How does the Catholic church deal with the differences between the God described in the old and new Testaments?

I have never found a satisfactory Catholic explanation of God's cruel nature depicted in the Old Testament, a depiction that is real enough for early gnostic Christians to believe the Old Testament God must surely be a different God to that of the New Testament. It seems this is an issue not discussed and, if it is discussed, only to the extent that the subject can be changed to a discussion of the occasional cruelty of the Israelites and finally an assurance that God is a God of love.

Let's be clear. When Exodus tells us that God sent ten plagues on Egypt, he hardened the hearts of the pharaoh and his people each time they were willing to let the people go. Forcing the Egyptians to undergo more hardship in this way can easily be seen as a sign of vindictiveness, as in:

Exodus 10:20: the LORD made Pharaoh obstinate, and he would not let the Israelites go.

According to the Book of Joshua, God ordered an excessive punishment for a minor transgression after the conquest of Jericho, saying that all Israelites who had taken booty from Jericho be put to fire (Joshua 7:15). Joshua had killed every single person in Jericho after its fall, so when God ordered Joshua to do in the city of 'Ai what he had done in Jericho (Joshua 8:2), he was ordering another genocide. In 1 Samuel 15:3, God orders yet another genocide:

1 Samuel 15:3: Go, now, attack Amalek, and deal with him and all that he has under the ban. Do not spare him, but kill men and women, children and infants, oxen and sheep, camels and asses.'"

Unlike many Protestant Churches, the Catholic Church has maintained that understanding the Bible correctly requires guidance because the modern reader can be taken aback, especially if he or she fails to take account of the many “dark” deeds carried out down the centuries, and also in our own day. This site ('Ask a Priest') says that we should be aware that the correct interpretation of these passages requires a degree of expertise, acquired through a training that interprets the texts in their historical-literary context and within the Christian perspective which has as its ultimate hermeneutical key “the Gospel and the new commandment of Jesus Christ brought about in the paschal mystery”.

Having counselled its readers not to attempt to understand the Bible unaided, 'Ask a Priest' responds to the question of how the Catholic Church reconciles the "wrath" "repentence" and violence supposedly perpetrated by God in the Old Testament by saying it is important to keep in mind that the texts of the Old Testament date back to a time when the culture and mentality of people was very different from our current situation. Otherwise the question is not really answered. I believe further that the person who would ask this question deserves a better answer than that we need to read the Old Testament in the light of the New Testament.

This site ('Catholic Stand: Living the Truths the Church Teaches') answers this question, rather dogmatically put by Richard Dawkins and more sensitively by John Beversluis, by saying that in the warlike world of the ancient Middle East, a God who did not smite your enemy was not really a God worth worshipping, and condemning the pagan gods as being equally warlike. The claims of a violent and vindictive God are entirely ignored and the author goes on to discuss the moral commandments of God.

The Evangelical Catholicism site sets out to answer questions of the possibility of God having commanded genocide. It refers to Dei Verbum promulgated by Pope Paul VI in 1965, quoting “The books of Scripture must be acknowledged as teaching solidly, faithfully and without error that truth which God wanted put into sacred writings for the sake of salvation,” but saying it does not teach that the texts are inerrant in faith and morals. The question is not at all about faith and morals and is therefore left unanswered.

None of the above speaks directly on behalf of the Catholic Church, which remains largely silent on the issue of the more violent nature of the Old Testament's God, especially in the Book of Joshua. Often the best answer to an unanswerable question is to studiously ignore it, and I believe this is the Catholic approach to this vexed question.

But the question is answerable and has been answered, even if not by the Catholic Church. Eric Jobe provides one answer in 'Understanding Violence in the Old Testament: Critical and Patristic Perspectives'. He says when we encounter violence in the Old Testament that unsettles us, we may take some solace in the possibility that these texts were never intended by their authors as reporting factual history. Rather, they reflect theological and ideological concerns as encountered by the communities that first read these books. Jobe is an instructor of Bible and biblical languages for the Orthodox Church in America.