If you decide you do not believe anything about God and His image within and, therefore, think that you do not have to fight this spiritual battle, you will find that eventually your inner instincts will compel you to do so. Even if your current identification with your ego and its physical body is so strong that you make no effort to further your spiritual evolution in this lifetime, the process goes on. The universal laws under which creation operates do not cease just because you make no conscious effort to find God. The truth does not need your approval in order to exist. As long as you continue to equate happiness with the satisfaction of your desires and the pleasure of your senses you will be denying yourself the long-term joy of satisfying your soul. Because you are bound to act in particular ways by your past actions (your karma) and your own innate nature (the influence of the three qualities of everything in creation), you must do what you are compelled to do, but you can learn to do those things without attachment to their results. You can do whatever you think will make you happy, but the result is not under your control, so you are fighting the spiritual fight whether you want to or not.