God is the same throughout the Bible.
It is true that the Old Testament tells us God is holy and pure, and He punishes those who rebel against Him. But the New Testament tells us the same thing. In fact, some of the strongest warnings about judgment in the Bible come from the lips of Jesus (see Matthew 7:14).
In the same way, the New Testament certainly stresses God’s love and mercy. In fact, it gives us the greatest proof that God loves us: Jesus laid down His life for our salvation (1 John 3:16). But the Old Testament also tells us repeatedly about God’s love for us.
Jesus Christ is the same yesterday and today and forever.
Billy Graham – Wisdom For Each Day