Prayers of the Tzaddik
Reader: Is there is a concept in Judaism of the prayer of a righteous person? That's why we try to have the most righteous person leading our prayers? Is the prayer of a tzaddik more important than our prayers?
Rabbi: There were times when God answered Moses' prayers (Gold Calf), and times He didn't. (Miriam) There are considerations of the individual, and those affecting all of Israel. There are sincere prayers, and those through which a person rushes, like unburdening a load. Many considerations affect a response from God. Thus, we don't know when God will answer someone, even as righteous as Moses, when he prays for others, or if action is also needed by the nation like King David says.
But we do know that God is just. So if a person truly needs something from God, and he or she is on a level deserving of it, God can answer, without a tzaddik praying for us. God will not hold back goodness from a deserving person, simply because he didn't have a tzaddik requesting it from God.
A wise Rabbi taught that the prayer of the person who is in need is the most important prayer before God. This makes sense, since the person in need will see whether his prayer goes unanswered and can then realize he is not deserving. He alone is in the position to perfect himself. In this case only, when one selects to improve himself, does prayer reach its optimal purpose, and deserves a response from God. But if the person doesn't improve, why should a tzaddik's prayers have any affect? If the person is a sinner, he doesn't deserve God's help, so a tzaddik's prayer will be ineffective.
Of course, we cannot know all God's considerations. Rashi said God answered Isaac and not Rebecca, since Isaac was a tzaddik whose father was also a tzaddik, while rebecca was a tzadekas whose father was evil. And the Talmud has a case where rain was needed so the people approached a tzaddik to pray, although this does not mean God will answer.
There are so many cases, so many factors...and to arrive at true principles we must know all cases, which we do not. The best we can do is to keep studying and following the principles we know as true, and abandon practices we have not yet proven. For God desires we live in accord with what our mind tells us is truth.
The best approach is that each person live in accord with Torah, removing his or her sins, and also help others live by God's word through educating our nation. In this manner, we are doing all we can to deserve God's blessings.