One and the Same
So he prayed to the Lord, and said, “Ah, Lord, was not this what I said when I was still in my country? Therefore I fled previously to Tarshish; for I know that You are a gracious and merciful God, slow to anger and abundant in lovingkindness, One who relents from doing harm.” (Jonah 4:2)
Sometimes people will say they believe in the God of the New Testament, but not in the God of the Old Testament. In their perception, the God of the New Testament is gracious and loving and merciful, while the God of the Old Testament is unforgiving, mean, and angry.
But the God of the Old and New Testaments is one and the same. He is the true and living God, and we see Him demonstrating love and forgiveness in the Old Testament as well as the New.
Take, for example, the story of Pharaoh when he was confronted by Moses. Moses told Pharaoh to let God’s people go, and if he didn’t, then a series of plagues would come his way. And that is what happened. A plague would come, Pharaoh would beg for mercy, mercy would be extended, and Pharaoh would harden his heart. This went on and on and on, and Pharaoh hardened his heart again and again. Thus he experienced the repercussions. But God gave him chance after chance.
When Noah built the ark, the flood did not come straightaway. There was a lot of time for the people to repent and turn to God. The Bible says, to the point, that Noah was a preacher of righteousness (see 2 Peter 2:5). That means Noah told people what was true. He told them how to get right with God. But they laughed at Noah. It became a form of entertainment to watch crazy Noah build his boat. That is, until the first drops of rain began to fall.
Nineveh was one of the most wicked cities that ever existed, yet the people repented and turned to God, and God forgave them.
God not only is presented to us in Scripture as good and loving and merciful, but also as righteous and just.
Summary: The God of the Old Testament and the God of the New Testament are the same God!