People say the God of the Old Testament is cruel and if you read it, it seems so.
It's really a matter of perspective though. Writers of the Old Testament ascribed everything in life to God, and since life can be cruel God comes off as cruel sometimes too.
If a city like Sodom is destroyed by a volcano, they felt compelled to come up with a reason so they said the people in the city were sinful and that's why God destroyed them.
I don't know if the people in Sodom were any more sinful than people anywhere else, but there have been several cities destroyed by volcanoes through the ages and people of faith want to know why.
It's hard for people to accept that we don't know why cities are destroyed by volcanoes: probably because they are built near a crack in the crust where magma can force its way through to the surface, but that's not a reason to say God is cruel.
The Old Testament, particularly the Torah, covers a vast period of time and these disasters stand out. It doesn't mean God is cruel though. There are other parts where God is shown as kind and merciful, but those parts aren't nearly as memorable as the more painful ones.
What's missing from the Old Testament is the Jesus message that all things work for the good, and even though life is cruel, it's not the end of the story--there is another life that comes after this one where justice and mercy reign.
If that message were clearer in the Torah and the Old Testament, then God would not seem so cruel. That's why it's so important that Jesus came when he did to give us this message of hope.
Children too think their parents are cruel when they don't get their way and it can take many years for them to understand how much their parents really loved them, especially in the dark times.
God is our parent and the bible is the story some of us wrote along the way of our life with God. There are parts of the story we didn't get exactly right because then and even now our perspective is that of a child and like a child we can't always see how much our parent loves us no matter what happens.
God isn't cruel. God loves us. That doesn't mean things will always be pleasant though. It does mean that we will make it through the unpleasant bits, then and now. There is love and there is hope, no matter what happens.