Modern Atheists have published a lot of ink criticizing the acts of God in the Old Testament. Popular writer Richard Dawkins makes it a central theme of his key works.
This blog has dealt with this previously, which you can find here. This week Ravi Zacharias’ Ministry have put on their website an excellent response by John Dickson. If you are at all interested in this question, I would encourage you to spend a few minutes of your life listening. You can download the MP3 file from RZIM, here. (Look for the Let My People Think broadcast titled “Violence In The Old Testament” by John Dickson).
Dickson makes several excellent points, not the least of which is that it is not acceptable to separate a historical account from the narrative explanation of that historical account. Yes, the Old Testament has God instructing Israel to kill the Canaanites. But it also has God saying that the reason is due to the wickedness of the Canaanites, and not because of anything good about Israel.
Dickson also points out that Dawkins & Co. do not give the Bible the same level of consideration they do with basic scientific theories, namely focusing on isolated data without bothering to read the models the experts use to interpret the data.
In reality, the God of the Old Testament is both merciful and just, showing the same grace as Jesus in the New Testament.