In this week’s Bible reading, Noach , we read about the dove that Noach sent to see if the flood waters had subsided and he could get out of the ark. If the dove came back it would be because the waters had not yet come down. If she did not return, it would be a sign that she had found a place to build her nest because the waters had gone down and she could get out of the ark.
The first time he sent the dove, it returned. A week later he sent it back and returned with a plucked olive leaf in its beak. A week later Noach sent it again and did not return. The waters had subsided and it was time to get out of the ark .
The image of a torn leaf in the beak of the pigeon in full flight became a very graphic expression of peace and tranquility.
Reading the texts describing how devastating the flood waters were, the question arises: where did the pigeon find an olive leaf in a world that had been submerged under water for months?
The Midrash  brings up two opinions on this subject: 1) the leaf was plucked from an olive tree in the Garden of Eden; 2) the leaf came from an olive tree in Israel where there was no flood.
Neither of these two answers are compatible with the Peshat, that is, strictly adhering to the text. Furthermore: if the dove brought him the leaf of an olive tree that grew in a place where there was no deluge, what benefit would there be for Noach regarding the situation in the areas where there was a deluge? Also: it is not logical to say that the waters did not also flood the land of Israel. It would be a miraculous phenomenon that does not flow from a simple reading of the texts.
Shouldn’t Rashi —whose objective with his commentary is to explain difficulties that arise in the basic understanding of the texts— give us an answer to this obvious question? The Rebbe —may his merit shield us— deduces from the fact that Rashi does not explain anything here that the answer is evident from a logical analysis of the texts themselves and nothing needs to be explained about it.
Let’s see how.
The text says that from the fact that the dove brought the leaf in its beak Noach knew that the descent of the water was already well advanced.
The logical questions are:
How did Noach know that the earth was already dry, perhaps the dove plucked the leaf from an olive tree at the top of a mountain and it would therefore not be an indication of what was happening further down in the plain?
Why did the dove specifically bring an olive leaf and not a leaf from another tree?
The olive tree is a very strong and resistant tree. It can be assumed, then, that of all the trees submerged under water, it would be the olive trees that would have the greatest chance of survival, at least some of them. At the same time, it should be understood that although the tree can survive, the leaves cannot survive being submerged so long under water. Logic then indicates that if we see a fresh leaf, it must be a leaf that sprouted after the flood was over. Since it was a freshly sprouted leaf, Noach was able to calculate, based on the time it takes for a new leaf to sprout, the situation of the descent of the waters.
Another precision in the text: the leaf that the dove brought in its beak was torn off, that is, it’s not that it found an old leaf floating around, but rather it was torn off the tree on which it found it. In other words, it was a leaf that began to sprout only after the waters had subsided enough for this to happen.
The Chassidic Dimension:
From the Chassidic perspective , the flood fulfilled a purifying function similar to that of a Mikveh. Immersion in the waters of a Mikveh can achieve two levels of purification: 1) purification from a state of impurity; 2) adding an even greater level of purity to something that is already pure.
From the perspective of the Peshat —the text without commentary—, that the waters of the flood also flooded the land of Israel, we can understand that the flood fulfilled these two functions of a Mikveh: 1) it purified the world from its state of impurity; 2) it added even more purity to the land of Israel.
Note: I want to clarify that the analysis in its origin is much broader and more complete. The synthesis here aims to introduce the reader to the concepts addressed and their style.
Source: Likutei Sichot Vol. 10 pp. 30-36