Muslims are very much about follow the rules and you go to Paradise when you die. The religion is designed to be rule followers. Mohammed was the political, military, and religious leader of his time so there was no separation and that non-separation has continued.
In Christianity, it is about choice. Granted some sects have veered from that over the centuries but for the most part it is a personal choice to believe. In fact, New Testament actually says you cannot believe for someone else. Therefore western culture evolved to independent choice with a respect to the 10 commandment laws.