Persistence

One of the books I recommend to beginning meditation students is Journey of Awakening: A Meditator's Guide Book by Ram Dass. Today I was thumbing through my copy and came across a passage about meditating whether you feel like it or not:

Many times in the course of meditation you will think of things you'd rather be doing. There may be moments of boredom, of sexual desire, doubt, or fatigue. At these moments you must call upon your faith. Faith in what? Faith in the power of meditation to change your awareness and your perspective about reality.
...
Along with faith comes the requirement for dogged persistence. At first meditation may bring you mild highs or some relief from suffering. But there may come a time - just as there does in the development of any skill - when there will be a plateau. You may be bored, discouraged, or even negative and cynical. This is when you will need not only faith, but persistence. Often you will find yourself in training that forces you
to sit when you wish you didn't have to. You subject yourself to this because something deeper within tells you to go on...

Even to the end of the journey faith is vulnerable. For example, though your faith may be strong enough to sit in meditation, if you mix with people who sneer at it, their skepticism may weaken your resolve. But if you stay with meditation, faith in your path will strengthen until you can withstand any criticism, even your own doubt and dark night of the soul.