There is a difference between a angry God and a just God.
In the beginning God created the heavens and the earth. When the very first verse of the bible is understood to it's fullest then the understanding of the events in the old testament can be seen.
From the time of adam and eve to noah God demonstrates his love, grace and mercy for his creation.
Providing a covering for our first parents shows God's love in a attempt for a continuous relationship with man.
Placing a mark on cain not to be harmed even though he walked away from the Lord shows God's mercy.
Taking enoch because he walked with God shows God's delight and reward.
Finding grace towards noah shows God's grace, love, reward and mercy towards his own.
Judgement came upon a people who went there own way with a total disregard of the creator.
They brought judgement upon themselves and their unbelief cost them their lives.
From Abraham to 70 ad God created a nation to be a light to the world. That this nation's history would show that there is a God and only one God. Judgement begins in the house of the Lord as this nation shows that there are blessings and cursings that come from above. How the word of God is truth and life.
And without him we can do nothing. That sin produces slaves and death.
That all the Lord had spoken is truth and sure. That he is the great I am from end to the beginning.
The history of Israel is the lord's footprint upon the earth. Proving devine intervention between God and man.