Deuteronomy 32:46 – For it is not an empty thing for you, for it is your life, and through this thing, you will lengthen your days upon the land to which you are crossing over the Jordan, to possess it.
Gemora Yerushalmi Peah – 1:1 – Rabbi Mana said: “It is not an empty thing, and if it is empty, from you it is empty”. Why is this so? Because if you had worked hard in it [you would have understood it.] This teaches that any issue that a Court works hard at to understand, [the issue] will ultimately be fulfilled through them.
Torah Temimah Colloquial Translation on Note #91:
The reason for this interpretation of the verse is clearly the extra word “from you”, this word seems to be superfluous. It could have simply said “For it is not an empty thing.” That is the reason why the rabbis deduced this additional teaching from the verse. That is, if you find that an issue cannot be understood, know that it is just ‘empty’ [not understood] from you; you have not toiled sufficiently to delve into the matter to find the explanation. However, if you do toil [put forth the effort], you will find [the explanation.] answer. This is according to the expression [in Chapters of the Fathers]: “if one says he has toiled but not found, don’t believe him.”.
Therefore, it is clear from this that any issue that the Court exerts much effort [puts their soul into] in clarifying and searching for the truth, that issue will ultimately be clarified and fulfilled through that Court. That is to say, according to their intent will it be understood. In the Jerusalem Talmud it uses the phrase “as though it had been given on Mount Sinai”. That phrase though is an exaggeration just meant to emphasize their intent to arrive at the true truth of the matter.
The specific phrase used “puts their soul into” finding out the truth of the matter, is used because all Courts desire to delve into the source and central issue for any given topic and they metaphorically give over their souls through their effort and toil. This fulfills the well-known expression: Torah cannot be [totally] fulfilled except by someone who [metaphorically] kills himself over it. Look over at my note in the beginning of Parshat Pekudei for a similar observation on the verse “As God had commanded Moshe”.
Editor’s Note: It seems to me that the central lesson of this note is: “no pain, no gain”. If something in the Torah is inexplicable to you, spend significant effort seeking to understand it. The rabbis are teaching that if you put in the effort, you will learn the wisdom that you need to know.