Parashat VaEtchanan discusses many vital ideas. One that is often overlooked is an interesting negative Mitzvah. The Torah (Devarim 6:16) commands, "Lo Tenasu Et Hashem Elokeichem KaAsher Nisitem BaMasah," "Do not test Hashem, your God, like you tested Him at Masah.” Before we start analyzing the Mitzvah, we have to understand what the Jews did in Masah. The events at Masah UMerivah occurred between Bnei Yisrael’s initial reception of the Man and Amaleik's attack. As related in Shemot Perek 17, the story goes as follows: The Jews are traveling, and they spend one night in Refidim. They run out of water, and become nervous about how they will survive. They argue with Moshe, and complain to him, demanding water. Moshe Rabbeinu responds to them by asking if they are trying to test God. The Jews then express the usual complaints—asking Moshe why he brought them out of Egypt to die, and why Moshe seems to want them all to perish from thirst. In response, Moshe calls out to Hashem expressing what the Jews were saying. Hashem provides Moshe with instructions and the situation is rectified. Moshe renames the place Masah UMerivah, because the Jews tested and challenged God.
After reviewing the story, we can ask about the prohibition in our Parashah. The entire concept of testing God is strange. What actions would violate this prohibition?
One way to find the answer is to look at what occurred at Masah. Bnei Yisrael asked for water. This would seem to imply that one cannot ask for water; obviously, this is not the case. So what was the Aveirah at Masah, and consequently, what does our Pasuk forbid? There are many opinions on this issue, but most of them agree that there is a fundamental link between the Aveirah of not testing God, and the prohibition of not trusting a Navi already established as trustworthy. The Rambam (Hilchot Yesodei HaTorah chapter 8) offers an interesting explanation regarding the trustworthiness of a Navi. He believes that before we can believe him, the potential Navi needs to predict something and then have it come true. The Rambam continues that once he is proven as a true spokesman of Hashem, he is never allowed to be challenged. If one does challenge this man, the challenger is in violation of “Lo Tenasu.”
The Sefer HaChinuch explains that while that Pasuk says literally not to challenge God, it means not to disregard a Navi who calls for repentance. Since God did not directly speak to Bnei Yisrael when they were at Masah, His word was relayed only through the prophets. From this as well, we see that challenging a Navi and his holy prophecies is like challenging God.
Despite our understanding of what is forbidden from our various sources, a passage in the Gemara (Ta’anit 9a) at first glance seems to disagree with these explanations. Rabi Yochanan was once walking around the streets, and he saw a child. He asked the child what he was learning, to which the boy responded that he was learning the source for taking Ma’aseir (tithes). The child asked him why the Pasuk “Aseir Te’aseir” (Devarim 14:22) has a double language. Rabi Yochanan responded that the double language teaches us that we take Ma’aseir in order so that we become wealthy. The boy asked him if this was true, and Rabi Yochanan told him to go out to the field and see if it was true. The boy responded with a question from our Parashah: He asked how he could go and put God to the test, by taking Ma’aseir as described by Rabi Yochanan. Rabi Yochanan answered that in most cases this is true, but this case specifically is an exception. He proved it from the Pasuk in Malachi that states, “Havi’u Et Kol HaMa’aseir El Beit HaOtzar ViYhi Teref BeVeiti UVechanuni Na BaZot Amar Hashem Tzevakot Im Lo Eftach LaChem Et Arubot HaShamayim VaHarikoti LaChem Beracha Ad Beli Day,” "Bring the entire tithe into the store house so that there will be food in My house, and try Me now, said Hashem Tzevakot, if I will not open the windows of heaven and pour out a blessing for you that there will be more than enough" (Malachi 3:10). The fact that a specific Pasuk teaching us the exception would imply that with regard to any other case, challenging God Himself is not allowed.
The Torah and these commentaries teach us not to be unduly skeptical of Hashem and His Torah. We know that the Torah allows us to question it and to look for deeper answers outside of its literal text, but this Mitzvah teaches that there indeed are boundaries that must be respected . God (and the Torah) is compared to a fire – If one stands too close he may burn, but if he moves too far away, he can no longer feel its heat. So too, one should not feel constricted by the literal text, but we are forbidden to stray so far to challenge God, lest we lose proper respect and connection with Him and His Torah.