Why do you repeat the club oath before you commence Tae Kwon Do training?

Primarily as a constant reminder to the student as to why you train, what the rules and responsibilities are, and that you should be conducting your daily life, inside the dojang as well as out, by following the tenets of Taekwondo.

It is also recited as a sign of respect for the instructor and school where you are studying taekwondo.