Why did God get such a makeover in the New Testament?

[Hi600]

In the Old Testament, God is mean and kills everybody. Eye for eye, tooth for tooth, bone for bone.

But in the New Testament, God is suddenly nice and tells us to be nice to everybody. Jesus is basically nice to the point of wimpiness, telling us to turn the other cheek when somebody strikes one of our cheeks. In fact, the only time where Jesus ever becomes mean is John 8:44, where  Jesus attacks the Old Testament God. (Jesus' infamous anti-Semitic rant where he claims that the Old Testament God is actually Satan and the Jews are actually Satan worshippers.)

So why did God have such a makeover in the New Testament?

Historically?  Because the people involved in cobbling together christian canon didn't believe in the same god or the same covenant or that they were the same people anymore.  Most notably, marcion, who produced the first nt and gave the folks he would later break with (and be called a heretic by) the very idea to do so and to form an identity around this body of work wholly separate from a jewish identity.  He very explicitly believed that jesus was a new and different and better god.  Made Paul™ famous, too.  Others were more nervous about the potential loss of the borrowed ladder - and that's been pretty much the status quo since.  Leaving us with a theology that claims continuity and a magic book that tries to establish a break.

Probably correct