Joshua 20 speaks about 'Cities of Refuge.' When people had committed a sin 'unintentionally' they needed a place to flee from the community who may have been keen on revenge. These cities offered a place of hope and safety. The sinners were secure in the walls of the city.
Isn't this what Jesus does for us? He is our 'city of refuge' - when we have sinned, we know that we can turn to him and he will not cast us out!
Psalm 46:1 - God is our refuge and strength, an ever-present help in trouble.