Our Gemara on Amud Aleph discusses several scenarios where there is an unresolved disposition of ownership:

 

In the case of two people who deposited money with one person, and this one deposited one hundred dinars and that one deposited two hundred dinars, and when they come to collect their deposit, this one says: My deposit was two hundred dinars, and that one says: My deposit was two hundred dinars, the bailee gives one hundred dinars to this one and one hundred dinars to that one. And the rest of the money, i.e., the contested one hundred dinars, will be placed in a safe place until Elijah comes and prophetically determines the truth.

 

The simple reading of this idiom is that when Elijah the Prophet will arrive to herald the Mashiach, longstanding halachic disputes will be resolved. The scriptural basis for this comes from prophecies of Yeshaiyahu (11:9 and 11:3) about the future messianic times:

 

In all of My sacred mount 

Nothing evil or vile shall be done;

For the land shall be filled with devotion to GOD

As water covers the sea. 

 

He shall sense the truth by his reverence for GOD:

He shall not judge by what his eyes behold,

Nor decide by what his ears perceive.

 

While there are more pashut ways to understand this prediction about the Mashiach, such as it is referring to a general wisdom and apprehension of the truth, the Gemara (Sanhedrin 93b) understands the Mashiach as literally deciding legal matters via divine insight. In a case such as our Gemara’s predicament, the Mashiach would know who the liar was. 

 

The Pesach Einayim on our Gemara says this is not a violation of the principle of the “Torah is not in Heaven”, which restricts a prophet from using prophecy to adjudicate a Torah law (Bava Metzia 59b). This is because here the Mashiach is simply acting like a lie detector test, revealing a fact. 

 

However, Halacha is not “fact”. It is not one decision, but is determined by the Rabbi or Sanhedrin with human intellect to understand how to apply the will of God, as expressed by that  mitzvah or halacha in a particular circumstance and time. This is how we can understand that the Gemara can say, “these and those (each side of the dispute) are both the word of the living God.” Ritva (Eiruvin 13a) famously explains that every halacha has 49 aspects to allow and 49 aspects to forbid. This suggests that different situations, as well as rabbinic assessments, require different ways to enact the various aspects. Consider the following metaphor: You want to show your spouse that you love him or her. What do you do? Maybe she wants a gift? What kind of gift? Maybe he wants to hear compliments or praise? If so, what kind? So too, each halacha and mitzvah is an effort to honor and fulfill God’s will. But we need to first understand all the dimensions and then decide what is the dimension that is most called for. Once upon a time, the rabbis may have even had a tradition of various aspects or considerations within each mitzvah, and rules when each consideration is primary, which at this point we can only make guesses about. (See Rambam’s introduction to his commentary on the Mishnah, in the section where he discusses halacha le-Moshe Mi-Sinai.)

 

Once we understand this principle, we can see how in our Gemara’s question we wait for Eliyahu to answer it, but in many other gemaras that have unresolved questions, the word used is Teyko. The word Teyko is often translated as coming from the acronym, “Tishbi Yetaretz Kushyos V’abayos - the Tishbite (Elijah) will answer the Torah questions and difficulties. While this derash on this word has been repeated by great sages and has meaning and depth as much as any derash does, which is to say a lot, it is NOT pashut peshat. Teyko is an Aramaic word which means, “Let the matter stand.” 

 

Now we can see how alternating the choice of the word Teyko for unresolved halachic questions, and the choice of the words “Ad Sheyavo Eliyahu” until Elijah comes, used for the resolutions of factual questions makes perfect sense. Halachic questions will not be answered in a miraculous manner during messianic times. There will be greater wisdom in general, and a functioning Sanhedrin, which will allow us to answer more questions, but the process will remain unchanged. Humans will still determine the answer, that is why we say Teyko, let it stand.  There is no miraculous Deus Ex Machina that will one day solve those problems. On the other hand, when we have factual questions such as not knowing who is lying, we will count on King Mashiach to determine the truth, as prophesied by Yeshaiyahu.