For the previous post on “Remez,” see:
The 3rd level of interpretation or understanding, after “P’shat” and “Remez,” is “D’rash.”
On the “D’rash level, meanings can be derived to fill in “blanks” in the narrative. For example, how could the B’nai Yisrael find acacia trees in the wilderness, where there would presumably be few or no trees?
“…the choice of using Atzei Shi’tim seemed to have been predestined and predetermined. The midrash (quoted by Rashi ibid 25:5) tells us that that one of the first things the Patriarch Yakov did when he entered Egypt was to plant Shi’tim trees for use in the Tabernacle [Miskan] over 200 years later. The use of this specific type of wood was clearly not to be a choice of happenstance.” 
A “D’rash” can also derive homiletic lessons from the text of Torah. For the present discussion, I differentiate these lessons from those in the “Remez” level, by saying that “D’rash” homilies refer more to attitudes, feelings and concepts than to specific actions, as in “Remez.” Of course, I invite readers to disagree if they wish. But just as the step from “P’shat” to “Remez” has to do with internalizing the Torah into our behavior, I offer “D’rash” as internalizing this even further, into our thinking and feeling:
ויעש את הקרשים למשכן עצי שטים
“They made the planks of the Tabernacle of acacia wood.”
אמר רבי תחליפא דקסרין, למד הקדוש ברוך הוא דרך ארץ, שאם בקש אדם לבנות בית מאילן עושה פירות, אומר לו, ומה מלך מלכי המלכים הקדוש ברוך הוא שהכל שלו, כשאמר לעשות לו משכן, חס על אילן עושה פירות, אתה על אחת כמה וכמה
Rabbi Halifa of Kasrin said,
The Holy Blessed One was teaching “derekh eretz”: If a person wants to build a home out of fruit trees, one could say to them,
“When the King of Kings, the Holy Blessed One, to Whom all belongs, asked for a Dwelling (mishkan) to be built for Him, He ignored fruit trees [asking only for acacia wood]. You [i.e. we] should do the same.” 
“In the eyes of the midrash, acacia wood is a humble, inexpensive wood. God commanded the Mishkan to be made of acacia to teach principles of derekh eretz — that is, the traits one should embody, in this case humility.” 
What does the “fruit tree” represent?
Perhaps it means something “fragrant” — something having an attractive aroma. In this case, it’s aromatic beauty is compared with the acacia’s lack of fragrance (assuming that acacias lack fragrance).
Perhaps it means something particularly colorful, especially when the fruit of the tree is ripe. In that case, it’s visual allure is compared with the plain, utilitarian quality of the acacia.
Perhaps the fruit tree is harder to find. If so, it’s being compared with a tree that was available and plentiful enough to be useful.
The midrash says that G-d didn’t ask for the rarest, most fragrant trees with the most beautiful blossoms to be used for His “dwelling.” He asked only for an accessible, durable wood.
In this case, the acacia tree, as part of the Mishkan, symbolizes the worship of G-d. The Midrash is therefore saying that G-d doesn’t require great opulence or sensual appeal (e.g. beauty) in worship. Rather, G-d accepts a plainness when combined with a readiness to serve — symbolized by the acacia tree.
Notice that “humility” isn’t being described in terms of a specific action. Rather, it’s a pervasive attitude that we’re to assume.
But if we do no more than learn this as something the Midrash said, we’re really still on the “P’shat” level. It’s only a simple thought. When we internalize it and begin cultivating that humility — i.e. a readiness to put our own will aside in favor of G-d’s — we’ve actually reached the “D’rash” level of understanding.
We see what this means when we recognize that there can be great academic scholars of the Midrash who know all its details and all the commentaries on it, but who are emotionally unmoved by it. Their intent is to master the information, while remaining emotionally aloof from it.
One might say, then, that the different levels of understanding represent far more than different sorts of ideas. Instead, I believe that they represent different levels of conceptualization; even different levels of consciousness, each another step on an increasingly deep, intimate, subtler continuum.
 Exodus Rabbah 9