How can you do something when you don’t understand what it’s meant for? What’s the purpose?

Easily. The Holy One, blessed be He, commanded it, and that is binding.
I asked you what is harder for you about tefillin than about all the rest of Jewish law. Do you understand everything else? So why did tefillin specifically set you off?

I’m trying to understand the core of Judaism. Why do religious people get up in the morning to put on tefillin? Because they have to—I understand that. But what’s their motivation? Habit? Love? Faith?
Why does the Rabbi get up in the morning to pray? Leaving aside the fact that he has to.

Are you asking about all the commandments and not specifically about tefillin?
The reason is a sense of obligation. Why do people perform moral acts? Because they feel obligated to be moral. By the same token, people feel obligated to observe God’s commandments.

What is a sense of obligation?

Look in the dictionary.

It’s a shame you’re answering me like that. I’m asking because I genuinely want to know.

Eliad, I guess the Rabbi is trying to convey a message with that kind of answer. For example, maybe the point is that if you try to look for a definition of the most basic concepts, eventually you’ll have to stop somewhere. That is, if the definition of expression A is expression B, and the definition of expression B is expression C, at some stage the process of definition has to stop somewhere. The logical stopping point is usually concepts that every person understands intuitively (like feeling, or obligation), and any attempt to define them further will only blur the definition. So in this case, turning to the dictionary probably won’t help much either. Sometimes, if the concept isn’t intuitively clear to you, instead of looking for definitions it’s better to look for examples of how the concept is used, and try to understand it from the context in which it is used in other cases. For example, when a person cares for his elderly parents, he does so out of a sense of obligation; or when a person refrains from stealing even in a situation where he definitely won’t be caught, he does so out of a sense of obligation.

Thank you very much, Oren. I’m trying to understand what there is in Judaism that causes a person to do an act, commandments. Is it a faith that boils down to 50/50?

I don’t think that’s something found inside Judaism. The motivation to do a worthy act is rooted in us at the most basic level—that’s how the human being was created. Judaism is only the guide to what the worthy act is and how to do it. Faith is the recognition that Judaism is the correct guide (and not Christianity or Islam, for example).

Got it, thank you very much!

The purpose of tefillin and prayer is almost the same thing in different words: drawing closer to God. A person who is not Jewish also always looks for a “guide” for life: a doctor, psychologist, counselor, halakhic decisor, good friend, culinary expert, and so on.

Just as there are ways to turn to them, so the Holy One, blessed be He, chose a way to “turn” to Him.

Who turns to God? Anyone who wants to, usually in times of difficulty.
When do people turn to God? There are several kinds of people who turn to Him: the regular ones out of habit, those who need help, the believers, and those who have no other choice/hope.

All of these turn to God at different times.
Why is it worthwhile to turn to God? Because there is nothing else besides Him; He is the greatest expert and has the immediate ability to help us.

You should ask: why do we need to prepare food and eat? After all, in the end we’ll just go excrete it in the bathroom—so why eat?
By contrast, prayer and tefillin are food for the soul; they have no waste product.

In Avot, Shammai said: “Do not make your prayer fixed, but rather supplication before the Omnipresent, blessed be He,” as it is said, “for He is gracious and compassionate” (Joel 2:13).

An interesting addition:

http://www.hyosef.co.il/?kt=115

Thank you, Moshe, but how can you do something that has no feedback? It’s one-sided.

Are you talking about praying? If so, who said there is no feedback? Even “no” is feedback! He doesn’t owe us anything! The children of Israel cried out to God, cried out to God again and again, and ten plagues passed before they left Egypt….
If everything you ask for—you get—then you’d be a spoiled child.

What do you mean by one-sided? Why do you want God to ask things of you for His sake too?

Hello Eliad.
I answered you according to your question. When you ask me about the meanings of words, I refer you to the dictionary. Do you really not understand what a sense of obligation is? I explained it through an example in the moral context and compared it to the religious context.
I don’t see my role here as explaining words. If there is something about the term “sense of obligation” that you don’t understand beyond the plain meaning of the words, then you need to formulate the difficulty and clarify it, and then maybe it will be possible to address it. If you don’t make the effort to formulate your difficulty clearly, don’t expect me to guess what you mean and answer you.

Fair enough. I didn’t write the question clearly. Sabbath peace.