Everyone is familiar with the Shema, the Jewish Pledge of Allegiance: "Hear O Israel, the Lord our God, the Lord is one" (Deut. 6:4).

"Oneness" is crucial to a proper understanding of God. In fact, Maimonides writes that the highest level of wisdom a human being can attain is to comprehend the oneness of God.

Why is "God's oneness" so central to our belief? Why do we declare the Shema twice each day and aspire to say these as the last words before we die? Does it really matter whether God is one and not three?

Before the creation of the world, only God existed. There was no separate entity in any form.

Even after creation, everything in the world remained part of God.

The only difference is that through the miracle of creation, God gave each human being free will. With this, we have the unique ability to think for ourselves and to act upon those thoughts. It's as if from within God, we maintain a certain autonomy.

Through the miracle of creation, God gave each human being free will, a certain autonomy.

Yet we're still part of God. Because that's all there is.

So what was the purpose of making us a separate entity from God?

Rabbi Moshe Chaim Luzzatto (18th century Italy) explains in his famous book "Path of the Just": The purpose of creation is to earn pleasure. The ultimate pleasure is attachment to God. Where is this pleasure most manifest? In the eternal World of Souls, where we have absolute clarity of God's unity, and recognize that we are totally attached to Him, as we always have been.

The autonomy of this world – free will – can mislead a person into thinking there is something else outside of God. Therefore it is a constant, lifelong challenge to overcome this illusion – and see that the only existence is God. That God is one.

Constant Mitzvah #2 – "Don't believe in other gods" – spoke about the Yetzer Hara, our self-destructive inclination to move away from God. We said that it is a mistake to follow the Yetzer Hara, because it is an illusion, a temporal gratification that is ultimately dissatisfying.

This mitzvah of "God is one" goes much further. If the Yetzer Hara exists, it must also be part of God. And if it's part of God, it is by definition good. Which begs the obvious question: How can the Yetzer Hara be good?

Think of an athlete, a world-class high-jumper. When the coach raises the bar, is he trying to make life difficult – or is he drawing out the athlete's potential? Of course the coach wants the athlete to succeed! And if he's a good coach, he knows the right time and amount to raise the bar. Of course, the athlete might fail to clear that height. But the coach knows that with enough concentration and effort, the athlete will succeed.

The coach knows that with enough concentration and effort, the athlete will succeed.

Since the purpose of creation is to earn eternal pleasure, the purpose of the Yetzer Hara must be to enable us to earn additional pleasure. So although the Yetzer Hara seems to be pulling us away from God, it actually provides opportunities to grow closer. Evil gives you another struggle for truth – so you can take pleasure in that discovery.

Without "challenge," there is no appreciation in doing the right thing. Instead, you're just doing what you'd naturally do anyway. All the challenges, all the nuisances, are only designed to bring out the best in you – not hinder you.

It is an axiom of Jewish thought that God never gives you a challenge which is too difficult.

Learn to read life's messages properly. When your Yetzer Hara comes and tells you to sin, he's really saying, "Here's a challenge. Let's see you overcome this one!"

We misunderstand evil because we take it seriously. We think it's an independent voice. But that's an illusion.

For example, what if you say, "I'd really like to learn Torah today, but I have a headache which prevents me from learning."

This is a misunderstanding of "God is one." Is the headache a nuisance that blew in from Mars? Of course not! This headache was especially designed to bring you closer to God – no less than prayer, charity, or any other mitzvah opportunity.

So why a headache? There are many different aspects to spiritual growth, and there's a certain lesson that a headache is coming to teach you. Part of your job is to figure out what that lesson is.

Everything in life is part of the same system, stemming from the same source, with the same purpose. Obviously, there are different pieces to the puzzle, different spiritual muscles which need to be flexed and exercised. But "bad" and "good?" It all has the same goal.

In the times of the Temple, a person who emerged from a difficult situation – e.g. someone who was sick and then got better – would bring a "Thanksgiving Offering." We could understand thanking God for getting better, but God is also the one who made us sick in the first place!

For that we are thankful, too. As difficult as it may seem at the time, the sicknesses and ordeals was somehow what this person needed in the overall scheme of life. Because of that ordeal, he is now a stronger person, a wiser person, a more compassionate person.

An ordeal makes one stronger, wiser and more compassionate.

We humans tend to look for the easy route, happy to find an excuse to "give up." A headache makes it harder to concentrate – so we think that gives us an excuse to stop. But really, since it's all part of "God is One," it's an opportunity to take on a new challenge.

This applies as well to setting goals in life. Of course we need to set milestones in order to make meaningful progress. But we mustn't set these plans in stone. They should be flexible enough to accommodate new challenges. That's God's way of steering and guiding us. He may "change the weather" to make sure we're heading in the right direction. But if plans are so clearly defined that they can't accommodate changes, that's a lack of belief in "God is one."

We must constantly battle the illusion that the forces of good and bad are fighting each other. In reality, every occurrence in life is all pointing in the same direction. "Bad" is a challenge which brings us closer to God – by giving us the chance to make the right choice and earn that closeness.