It is an opportunity to realize and become conscious of an Supreme Reality. You've got to live it. Just like one's physical fitness is determined by the strength of the body, one's spiritual fitness is determined the feeling of oneness, the desire to be with the divine all the time and the strength of one's will power. In reality, religion and spirituality are the same.
Spirituality is at the core of all religions.
However, all religions have forgotten this core and fiction seems to have replaced fact. Religion has come to mean 'blind organized faith' and has become dogmatic and fundamentalistic in its views. It is based more on personal experiences rather than the experiences of others. Since the Divine is universal, there is no religion in yoga. There are various philosophical approaches to yoga, but the aspirant is free to choose whatever path he deems fit.