A passage from Jeremiah 17:7-8
Blessed is the man who trusts in the LORD, whose hope is the LORD. He is like a tree planted beside the waters that stretches out its roots to the stream: It fears not the heat when it comes, its leaves stay green; In the year of drought it shows no distress, but still bears fruit.
I am always struck by this quote from Jeremiah because it is an image that recurs in the writings of Teresa of Avila time and time again. She describes prayer as being like a gardener wishing to water a garden. He starts by drawing water from a well -- a hard process, with little to show for it. After time doing this, prayer becomes easier, like a well with a pump. In the third stage, it is like having a nearby stream that irrigates the garden with water continuously. In the fourth stage, it is like rain falling from Heaven -- the rewards of prayer are showered on the person doing the prayer. (I'll have to look up the quote -- it is either from The Way, or the Life, or the Interior Castle).
The quote from Jeremiah speaks of trust. Prayer is something like an act of trust -- to a person not convinced that God hears prayers, it is an act of trust to pray -- you hope the time is well spent. It seems like a lot of effort, and if there is a reward, it can seem small. But the more one prays with confidence and trust that the prayer is heard, the more the rewards are apparent. The tree grows because the water is there; it withstands even those periods of drought. A person with a strong prayer life is indeed like that tree, and can withstand the most difficult situations.
Of course, a skeptic will say "Why does God put a person in difficult situations if he hears the prayer? Why doesn't he simply bless a person so that no difficulty at all falls into their lives?" The answer is complicated. We do not know God's will, we do not know all the situations he is trying to resolve. If you think of all the interactions of people and things in the world, and consider that there is purpose, life becomes immensely complicated. Take into account the actions of people with free will -- and God respects our free will greatly -- and the situation becomes even more complicated. To me, it is as if God sits atop a great hill, and we are walking up a torturous path to get to him. The path winds and twists many times before it reaches the summit. God, looking down from above, can guide us through this maze, if we are open to him, but like a maze, sometimes the easy path is the wrong one. Sometimes we have to backtrack a long distance before we can make progress going forward. The path makes no sense to us, because we do not have a map, and we do not have the view from above. We simply have to trust that when he speaks to us, he is speaking with our best interest at heart.
Sometimes his words are hard, and the path is difficult. Sometimes it takes years to understand and gain persepctive over events in our lives. And sometimes his purposes for us involve the cross -- for our good, or the good of those around us.
We have to trust that the reward is there. Like the tree in Jeremiah, we have to trust that the stream is there, even when the ground is broken by drought.