Mother Teresa was a Saint. Yet Mother Teresa was so doubtful of her own Christian faith, that she feared she was being a hypocrite. In a 2006 book that compiled letters she wrote to friends, superiors and confessors, her doubts are obvious.

Shortly after beginning work in Calcutta’s giant slums, she wrote: “Where is my faith? Even deep down … there is nothing but emptiness and darkness. … If there be God — please forgive me.”

As her fame increased, her faith refused to return. Her smile, she said, was a mask. “What do I labor for?” she asks. “If there be no God, there can be no soul. If there be no soul then Jesus, you also are not true.”

“These are letters that were kept in the archbishop’s house,” says Brian Kolodiejchuk, the priest who made the case for Mother Teresa’s sainthood.

He said her obvious spiritual torment actually helped her cause. “Now we have this new understanding, this new window into her interior life, and for me this seems to be the most heroic,” says Reverend Kolodiejchuk.

Perhaps Mother Teresa would have felt better if she had read the words of the great Muslim philosopher Al-Ghazzali (1058-1111) who said, "Doubt is to find truth. Those who do not have doubt cannot think. Those who cannot think, cannot find truth."

Or if Mother Teresa had studied Midrash (the Jewish way of expanding Torah teachings) she would have understood her spiritual situation better.

Everyone who devotes his or her life to a great cause, often has feelings of futility and self-doubt.

The Torah tells us that after the sin of the golden calf, God told Moses to hew two new stone tablets and God would again engrave them with the ten commandments. (Exodus 34:1) But from where did Moses get the stone?

The Midrash relates that Rabbi Levi said; from under the heavenly throne of glory; and Rabbi Yohanan said; from inside his own tent.

For Rabbi Levi the 10 commandments (both the content and the vessel) are from heaven. But for Rabbi Yohanan the content is from God; but the vessel is from human beings, indeed from within your own tent.

For Christians, the certainty of belief in a trinitarian Jesus is central to personal salvation. But Islam and Judaism make loyal submission to God’s decrees central. A modern religious fable makes this clear.

Once a sleeping man thought he heard God say there was holy work for him to do. God showed him a large rock and told the man to push against the rock with all his might. The man did this, day after day. For many years he toiled from sun up to sun down, his shoulders set squarely against the cold, massive surface of the unmoving rock, pushing with all of his might.

Each night the man returned to his cabin sore and worn out, feeling that his whole day had been spent in vain. Discouraged he started thinking: “I have been pushing against that rock for a long, long time, and it hasn’t moved. The task is impossible. I am a failure. Why kill me over this? I can just put in my time, give a minimum effort; and that will be enough.”

But then the man decided to study some Torah wisdom from the book Pirke Avot to counteract his troubled thoughts. “Lord,” he thought, “I have labored long and hard in your service, working with all my strength to accomplish your holy tasks. Yet, after all this time, I have not budged that rock even an inch. What is wrong? Why am I failing?

The Lord responded compassionately, “ I asked you to serve God in holiness and you accepted. I told you that your holy task was to push against the rock with all your strength, which you have done. I did not say that I expected you to move it all at once by yourself:

“You are not going to complete the work by yourself, but you are not free to avoid your holy task of pushing.” (Avot 2:20)

Now you come with your strength spent, thinking that you have failed. But is that really so? Look at yourself. Your arms are strong and muscled, your back sinewy and brown; your hands are callused from constant pressure, your legs have become massive and hard. Through opposition you have grown much, and your abilities now surpass what you used to have.

True, you haven’t moved the rock. But your holy commitment was only to try to push as much as you can and to exercise your trust in Torah’s wisdom:“Be like the workers who serve loyally without seeking a prize.” (Avot 1:3)

That you have done, and you have become holy. If you keep pushing you may find that in some wholly unexpected way the rock will move. That is one result of holiness. Even if the rock doesn’t move in your lifetime, you will become holy by trying to move it.”

At times, when we do God’s good deeds, we expect to see the results we want, and think we have failed if we don’t get them.

But basically what God wants from us is a holy commitment to submit to living our lives by God’s good deeds, and persevere in trusting God: “He has told you, O mankind, what is good and what the Lord requires of you but to do justice, and to love kindness, and to walk humbly with your God. (Micah 6:8)

As the Qur’an states: “Indeed, the believers [Muslims], Jews, Christians, and Sabians—whoever truly believes in God and the Last Day and does good will have their reward with their Lord. And there will be no fear for them, nor will they grieve.” (Quran 2:62) So pray as though everything depends on God. And do good deeds as though everything depends on you.

Rabbi Allen S. Maller has published over 450 articles on Jewish values in over a dozen Christian, Jewish, and Muslim magazines, and web sites. His most recent books are “Judaism and Islam as Synergistic Monotheisms’ and “Which Religion Is Right for You?: A 21st Century Kuzari” both available on Amazon.