So does the Bible present us with two conflicting Gods? The good God of the NT and to use the words of a prominent atheist author Richard Dawkins – “a moral monster and bully” of the OT. 

No. The Bible presents one God, and it becomes clear through progressive revelation in the Bible that God is both ‘gracious’ and ‘just.’ Both the OT and NT depict these qualities. 

While it is true that one clearly sees the evidence of the grace of God in the NT that concludes at the cross of Jesus Christ, it does not mean that the God of the OT failed to depict grace. 

In the very beginning, in the book of Genesis, God’s grace is evident in the Garden of Eden; after Adam and Eve’s collapse to sin, God pursues them with grace instead of wiping them out.

Likewise, the OT is filled with the grace of God. He graciously tolerates the people of Israel even after their repetitive rebellion and, also other nations, for example, in the case of Sodom and Gomorrah where He was willing to spare the city for the sake of 10 righteous people.

Now just as God’s grace is seen in the OT, His justice is evident in the NT as well. 

To name a few examples; Jesus clearing the temple (John 2) or the hardening of the hearts of the Jewish nation (Romans 11), not to mention the book Revelation that lays out God’s final justice and judgment that will take place at the end times.

In conclusion, the Bible does not portray a dual-headed God, but it unveils to us the totality of God’s whole nature. God is Just and full of Grace.