At first this question might sound silly since it is one Bible, but many feel that the Old Testament and New Testament describe different Gods. The usual reference is to how God seems to be more vengeful and less loving in the Old Testament, and more loving and less vengeful in the New Testament. But, if you look closely you will see this is not true.
While there are many rules given in the Old Testament, and many limitations given to God’s people, this is not at all vengeful or mean. God knows that His people need strict guidelines to keep them from the sinful ways of Israel’s neighbors. There is also punishment associated with breaking the laws, but this is actually a loving thing to do. I say this because our nature is to break laws, and the threat of punishment actually helps us to seek to do right.
In the Old Testament there is much to be seen of God’s love. The Israelites are regularly turning away from God and seeking their own way, and God consistently is giving them the opportunity to come back to Him and receive forgiveness. God’s grace is given abundantly in the Old Testament.
In the New Testament the focus is on Jesus Christ (the Son of God, God in the flesh) and His bringing the light of God to the world. Jesus brings the truth of God’s love and forgiveness in His teaching, but even more in His sacrifice on the cross. Yet, Jesus regularly teaches about the punishment that will be received for those who reject Him. Jesus talks about the existence of hell for all who choose to not believe in Him. So there is vengeance and punishment mentioned in the New Testament as well.
We see that God is consistent throughout history described to us in the Old Testament and the New Testament. In fact, many of the scriptures of the Old Testament are prophecies that explain what will come about in the New Testament. He has established laws to govern us, and punishment for those who fail to abide. God gives us many opportunities to be forgiven if and when we turn from our sinful ways and seek Him out. He regularly shows His love, care, and concern for His followers.While there could be much more said about this topic, my intent here was to give a simple synopsis on the constancy of scripture and the God of the scriptures. As we are told in Hebrews 13:8, “Jesus Christ is the same yesterday and today and forever.” Jesus, being God in the flesh, expresses to us how God is the same forever as well. Blessings.