The ancients thought God to be all things, both good and evil. Christians are the ones who separated the 2 because logic dictates if you are good, doing evil negates this.
I can supply personal experiences that good does exist. As for God, this was the ancients way of defining the undefinable. Even present day believers who do not understand how something wonderful has happened conclude 'God did it'.
"Every mystery ever solved has turned out to be NOT magic." -- Tim Minchin 'Storm'