What we have to remember is that the Old Testament prophets did not write the books of the Bible themselves. This was done by interpreters hundreds of years later.
So, as we see with the disciples, there is a lesser level of understanding - an orthodoxy, a primitive worldview, a worldly interpretation which we do not see with Jesus or the prophets themselves.
Those who had direct contact with God are not those who wrote down the books of the Bible.
There is a large margin for error.
So where it says that Samuel cut a man to pieces in front of the altar this may not have actually happened. Either Samuel has misunderstood God or the writer of Samuel has misinterpreted the story.
In my experience God does not act violently towards anyone. The violent stories in the Bible are misinterpretations of God's word or of historical events.
Most often it is an overlaying of assumptions of rewards and punishments projected from worldly authority figures like kings or pharaohs.
God is beyond violence.
God does not resolve conflicts with violence.
God waits for us to respond with love and compassion, even for our enemies.