Sometimes I think we are not talking about the same God. The first one, the one's tribe God, the other, the God of all of us. The first, a punisher God, the last one, a forgiving God. The first one, worried about old traditions, the last one, taking care of love.
I think the anciend idea is still not overtook... What do you think?
You aren't alone in this perspective. I would say the majority of Christians view God in the OT and NT this way for years or decades.
Consider that a lot of the OT is a narrative of God's interaction with people who are rejecting God, but the NT illustrates God's interaction with people who's sins have been paid for and often explains Truth rather than illustrating it in an environment of people who won't stop sinning.
The OT shows us a picture of what happens to people under the old covenant, which is basically: people failing to keep the old covenant by persistently being immoral. The NT shows us a picture of people under the new covenant God granted through Jesus' death. They can still sin and reject God with bad consequences, however the approach is all different. The teaching is no longer how people must obey the Law of Moses to be forgiven, but that they don't have to obey the Law of Moses to be forgiven and instead are already forgiven because of Jesus' sacrifice. (He obeyed all the Law "for them.")
The Bible only reveals one God to us, but who he is and what he is like is more comprehensively shown to us by seeing him in many different contexts. God is still a consuming fire (Deuteronomy 4:24), but the relationship you can have with him is based on completely different things. If you are submitted to God, then God is not someone you are contending with, but is someone who your enemies must contend with.
... God has said, “Never will I leave you; never will I forsake you.” So we say with confidence, “The Lord is my helper; I will not be afraid. What can man do to me?” (Hebrews 13:5b-6, 1984 NIV)
To some degree the problem with the perspective is in seeing quantity instead of quality. You can read all kinds of things about the "NT God" in the OT by reading about the people who were loving and/or obeying God, such as Abraham, Elijah, Elisha, David, Ezra, Nehemiah, etc. (the parts where they weren't dealing with the sins of the people).
