I always like to use school as an analogy to religion:
Accepting a religion is the same as registering for elementary school. Teachers in school are analogous to Guru's/Prophets - they guide you with their wisdom. Of course, it is ultimately up to us if we choose to follow our teacher's rules, but as we all know, we fail school and have to repeat the course until we choose to accept the teacher's rules.
Similarly, this life is our "school" if you will. We come to this life repeatedly until we correctly do everything Guru Ji has instructed. Only when we pass Guru Ji's School, we have attained spirtual discipline and taken full advantage of life.
So what exactly is "spiritual discipline"? According to Buddhism, one has attained spiritual discpline when he/she realizes that everything in the world can be broken down into atoms, then elementary particles (as suggested by Physics) and then into "Spiritons" - these "particles" are God's light. Everything in the world is made from God's light - the one thing that cannot be broken down any further.
In other words, we have been enlightened when we finally come to realize that everyone and everything is made of God's light. Once we realize this, we see no difference between the poor and the rich, between money and dirt, etc...
Now you may ask, why did God create this school? why did he create us and make us go through his school? This is a very deep question and fortunately the answer has been provided already in Gurbani: God's creation (Life) is his "play", his amusement. His "test" to see who overcomes all his challenges. Think about it, wouldn't you have created something if you were God?