But maybe the truth was true for its time? Who guarantees that this is the truth for the 21st century?

I don’t understand. Do you see anything here that depends on time? This is a value judgment.

What does “in the end the good will come because of it” mean..?

Maimonides wants to make clear that he does not dispute the existence of reward and punishment. He only argues that serving God should not be done because of reward and punishment. Fulfill the commandments because that is the truth, and in the end the good will come.

What is the reason to do the truth because it is true? (Or in other words, what does “truth” mean in this context?)

I don’t understand the question. You could ask the same thing about whatever reason I might give you. Truth is its own reason, and that is its essence. It does not need a prior reason before it. It is like asking why what is right is right. It is right because it is right.

Why are God’s commandments considered truth? Is adultery, theft, and muzzling an ox while it threshes falsehood?!

The sentence “Do not murder” is not a proposition but a command. Something that is not a proposition cannot be true or false, because it does not describe anything (see my article on Maimonides’ eighth principle).
What I said was that observing Jewish law is the correct way to conduct oneself, not that the statement “Do not murder” is true. My claim is that this is the right and proper way to behave, not that some proposition is true. If you insist, perhaps the proposition “It is forbidden to murder” is true in some sense (it will lead to the repair of the world), but the command “Do not murder” is not a proposition, and likewise here.
It is like moral commands. There too, the proposition that forbids murder is not true or false. Rather, one must not murder because it is not proper to do so.

I think such a basic issue needs a long and reasoned clarification. Notice that the writers here do not understand what you are writing, and you dismiss them with a kind of unclear saying, and that’s it.
We are talking about someone who thinks there is no punishment for transgressions and no reward for commandments, and yet you think there is still something obligating him to keep the Torah. For heaven’s sake, what is that obligating factor? Why, if God commanded and wanted something [in the past tense; I don’t know about the present], is that a reason that I, as His creature, who developed intentionally or by chance, ought to do it?
Do you see a philosophical reason why an intelligent robot [or a clone] created by a human being would be obligated in anything to its creator, rather than becoming an independent being with desires of its own? Is a son created by his father morally obligated to do every command that pops into his father’s head?
We are dealing here with the most basic foundation of all our obligations in the commandments according to your view, and I am astonished that you hardly explain it.

In another thread I saw that you compared this to moral laws that people keep on their own, not for reasons of reward.
And indeed, as they commented to you there, a normal person also does not keep moral laws because they are ‘right,’ but because he feels bad about himself if he does them [we were born with a conscience, what can you do. Hitler already complained about that]. But even if we assume they should be done because of their truth and value, that makes sense only in something a person accepts as a binding truth. But in our issue, notice that no one understands why we need to spend our whole lives fulfilling the desires of the one who created [or tuned] creation. Why is that a binding reason? If He doesn’t want us, let Him kill us; if He wants to keep us, let Him let us live.
[And especially the prohibition against destroying oneself is absurd. If I want to take my own life, that means life is only a burden for me, so how is His command supposed to be a reason for me to refrain from it?]

You yourself brought the explanation and the analogy to morality. Whoever does not accept the existence of an altruistic act—good for him (though I would keep my distance from him in that case too).
You decided that in our issue no one understands why one should observe. If you want to declare that in the name of the whole universe—fine. But it turns out there are probably quite a few who do understand it. On the contrary, even those who look for reasons and invent reasons that are unconvincing, in my view, are simply unaware that they have an intuition that there is an obligation to obey God’s command, just as there is an obligation to obey morality. This thing does not require explanation, because it is a basic intuition.
That is what I have to say. If you have a concrete question, you can ask. If you disagree—then you disagree.

Hi. The Rabbi wrote to Eliezer that this is a basic intuition, even though there are people who are not aware of it.
A. But does it really exist within them? Who says so?
B. To me the Rabbi wrote that this is parallel to asking why what is right is right. Is that a different answer from the one the Rabbi gave Eliezer?
C. The Rabbi’s analogy to Maimonides with the sentence “what is right is right” only highlights the way Maimonides begs the question. A person can determine what is right for him according to some value he arbitrarily set for himself as a goal. The commandments are truth. Their goal is truth. But what is that goal? Without a goal (which is the state we call “just because”), this is not right.
D. I can accept that the goal of the commandments is not known to human reason, but we are confident in the rightness of the path because someone greater than us instructed us to walk it. That is, the arbitrary goals of a person are false, whereas the divine goals are true, since He created everything and knows everything. A mother knows what is best for her daughter. God knows what is true and right for His creatures. But according to this, it is not clear why this is service out of love.
Pleasant afternoon.

I think I explained my position well. I simply do not understand what the discussion is about. You don’t accept it? Fine. So what is the point of repeating yourselves again and again?!
A. Let them examine themselves and see whether it is there or not. I am not supposed to discover for people what exists within them. But they should examine honestly and not go by a first impression.
B. No. It is the same answer.
C. I already explained. Truth does not require explanations or goals. Truth is itself the goals.
D. Here you are repeating what I wrote. That is exactly what I am arguing. Love is nothing other than doing the truth because it is true. That is what Maimonides writes in the passage I quoted above. Love of the Holy One, blessed be He, is not an emotional matter. See Column 22 and my article on emotions in Jewish law:

משמעות אפלטונית לרגשות בהלכה

Sorry. I didn’t mean to annoy you.

All good 🙂