From my experience, non-Christians (and some Christians) sometimes assert that God is a monster in the Old Testament but somehow loving and Fatherly in the New.
Robin Schumacher over at CARM.org explains:
Non-Christians sometimes assert that God is portrayed in the Old Testament as a cruel and ruthless deity that indiscriminately orders the execution of seemingly innocent men, women, and children, or directly carries out their deaths by various means. Such a God, the argument goes, in no way represents the loving Creator or Father figure that the New Testament offers, and should in no way be worshipped or venerated. However, a closer examination of Yahweh in the Old Testament refutes the charge of the Creator being a tyrant and instead reveals a righteous, patient, merciful, and loving God who does indeed mirror the picture painted by Jesus and the rest of the New Testament writers.
I highly recommend reading the article.
Go on. Check it out.
But there’s another aspect to the discussion that is oft overlooked.
God is a jealous God and will protect all whom are His
Exodus 34:14 explains, “you shall worship no other god, for the LORD, whose name is Jealous, is a jealous God.” God is speaking to His people with whom He has established a covenant (see Exodus 34:10).
God protects His own and woe to those who oppose His people.
Folks see God as a vindictive and horrific monster. I can understand that false perspective.
Leviticus tells us, “Whoever blasphemes the name of the Lord shall surely be put to death. All the congregation shall stone him. The sojourner as well as the native, when he blasphemes the Name, shall be put to death.”
God is jealous for His name; He desires His name to be praised and adored among His people and all who do not will be judged.
You will not understand this until you recognize the Old Testament is written from an insider perspective;
people who are God’s people see the Old Testament as an expression of God’s love for them
The New Testament expresses the same idea. God loves His people; God loves His people so much, He gave His only Son to die for all those who believe in Him. And for those who don’t revere His name and believe in Him will perish.
This is the greatest expression of love, in that, while we were yet sinners, Christ died for us. The whole of the Old Testament testifies to this, and the New Testament explains it.
Both Testaments possess this single truth:
Hell is eternity in the presence of God without a mediator. Heaven is eternity in the presence of God with a mediator, the Lord Jesus Christ.1
Thanks be to God for His unspeakable gift!
1Eternity Without a Mediator by Tim Challies