Why do Catholics follow the Ten Commandments?
The Ten Commandments were given by God to the Israelites on Mt. Sinai after they left Egypt. They are considered divine law because God himself revealed them to help his people live holy lives. They formed the basis of Jewish life, so Jesus followed them, too.
The Commandments are standards of holiness for Christians, too. Obey them and eternal happiness is ours. Disobey them and we suffer the consequences. Jesus summarized the spirit of the Commandments in
Matthew 22:36-40.