This is one of the common accusations from the “New Atheists.” They draw their conclusion from reading the violent passages in the Old Testament. They use this moral charge as the reason to deny the God of the Bible is a good God. These atheists don’t believe God exists but if He did, He would not be worthy of following.
The major problem is these individuals don’t take a careful look at the Old Testament text. They make multiple hermeneutical errors in their interpretation. If you are going to attack Christianity, then read the Old Testament the way it was supposed to be read. This they don’t do and don’t care to. They are on the attack and careful Biblical interpretation is not important.
The author of the book “Is God a Moral Monster,” Paul Copan, wrote an article for the Evangelical Philosophical Society. In this commentary he makes a reasoned critique of this charge against God.
The new atheists are certainly rhetorically effective, but I would contend that they have not handled the biblical texts with proper care, and they often draw conclusions that most Christians (save the theonomistic sorts) would repudiate. And this judgment is not the refined result of some post-Enlightenment moral vision, but the biblical writers themselves point us toward a moral ideal, despite the presence of human sin and hard-heartedness. These new atheists give the impression of not having the patience for careful, measured replies, yet this is exactly what is required. John Barton warns that there can be no “simple route” to dealing with OT ethics. Bruce Birch considers OT ethics as something of a “patchwork quilt.” Thus, it calls for a more subtle and cautious approach than the new atheists take….
My chief object is to outline a nuanced response to the new atheists' charges in order to discern the powerful moral vision of the OT. While acknowledging the drastically different mindset between [ancient near eastern context] and modern societies, we can overcome a good deal of the force of the new atheists' objections and discern the moral heart of the OT, which is a marked contrast to the new atheists' portrayal. Indeed, a number of the moral perspectives within the Law of Moses (for example, laws regarding restitution or gleaning to aid the poor) can offer insights for us moderns….
1. The Law of Moses is embedded in a larger biblical metanarrative that helps illuminate ethical ideals in ways that mere law-keeping cannot….OT historical narratives often present role models in action who make insightful moral judgments, show discernment, and exhibit integrity and passion for God-aside from the Prophets, the Psalms, and the Wisdom books, which also provide moral illumination. According to John Barton, the OT ethical model incorporates the imago Dei, natural law, and obedience to God's declared will, and we see narrative undergirding and permeating each of these themes. Brevard Childs observes that the Torah's legal material is consistently intertwined with narrative, thus providing “a major commentary within scripture as to how these commands are seen to function.”… we move beyond the Pentateuch, the same themes continue. Stories illustrate ethical living with role models who live wisely, show graciousness, and make remarkable sacrifices….
2. We must allow the OT ethical discussion to begin within an [ancient near eastern] setting, not a post-Enlightenment one….According to Bruce Birch, we moderns encounter a certain barrier as we approach the subject of OT ethics. Simply put, the [ancient near eastern] world is “totally alien” and “utterly unlike” our own social setting. This world includes slavery, polygamy, war, patriarchal structures, kingship, ethnocentrism, and the like….
The new atheists miss something significant here. They assume that the [ancient near eastern] categories embedded within the Mosaic Law are the Bible's moral pinnacle. They are, instead, a springboard anticipating further development-or, perhaps more accurately-pointing us back toward the loftier moral ideals of Genesis 1 and 2 and even 12. These ideals affirm the image of God in each person, lifelong monogamous marriage, and God's concern for the nations. The implications from these foundational texts are monumental….
3. The OT canon manifests a warm moral and spiritual tone as well as a redemptive spirit, urging national Israel toward a more noble ideal than is possible through legislature….
The new atheists tend to view OT ethical considerations in a static manner-a one-size-fits-all legislation for all nations. They fail to note the unfolding “redemptive-movement” of God's self-revelation to his people even within the OT. As we read the Scriptures, we are regularly reminded of an advancing, though still-imperfect, ethic on the surface while various subterranean moral ideals (for example, the divine image in all humans, lifelong monogamous marriage, and Yahweh's concern for the nations) continue to flow gently along. Yahweh redirects his people morally, theologically, and spiritually to move beyond the mindset of surrounding cultures.
I highly recommend reading Copan’s book, “Is God a Moral Monster.” In this work he takes on many of the major objections raised by detractors such as the new atheists.