The Baal HaTanya, in tomorrow's Tanya explains that when we simply contemplate the reality of HaShem's presence and truly believe and know that He permeates everything and all is negligable in reference to Him, we can arrive at unparalleled levels of joy. This he says, being aware of HaShem, is the underlying mitzwah in all other mitzwoth, as Chabakuk revealed. (צדיק באמונתו יחיה)
The Noam Elimelech (Parashath Balak) explains that a Tzaddik has the ability to perform miracles and bring down phenomenal blessings through his sheer cleaving to HaShem, just by speaking, anything is possible. What's the limit on the Tzaddik's ability? He can only affect those who put their trust and belief in him. In order to affect those who don't believe, he must take some physical action in order to perform wonders. This is how he explains Mosheh Rabbeinu hitting the rock: He says that Tzaddikim think only about the wellfare of the nation, even to the end that they will (on occasion) condemn themselves to gehenom in order to bring divine mercies down for Bnei Yisrael. Mosheh thought if he simply spoke to the rock that any members of Bnei Yisrael who had any doubts about him wouldn't be part of the miracle, and so through performing a physical action, he hit the rock, he brought out many waters, enough for even the most distant. Clearly, the Noam Elimelech adds, HaShem agreed with him because the miracle ocurred.
So, important life lesson, emunah in HaShem and His tzaddikim will save you a lot of hardship when you may otherwise be needlessly limiting yourself. In this way we open ourselves to divine intervention and holy miracles.