G‑d’s promise of material wealth and prosperity is dependent especially upon the Jewish people’s observance of His “rules,” i.e., those commandments for which there is no rational explanation.
Experiencing Divine Goodness
אִם בְּחֻקֹּתַי תֵּלֵכוּ וגו': (ויקרא כו:ג)
[G‑d instructed Moses to tell the Jewish people,] “If you advance in My rules.” Leviticus 26:3

G‑d’s “rules” are those commandments that defy rational explanation. The word for “rule” in Hebrew (chukah) actually means “engraved.” When a letter is engraved onto something, the letter becomes a permanent part of it. (This is not the case when a letter is written on something, for then the letter remains a separate entity from it). In the same way, it is by observing G‑d’s “rules” that we truly unite with Him. The reason for this is because just as letters are engraved in stone by removing what was there before, observing G‑d’s “rules” requires us to “remove” – i.e., negate – our egos. With our egos out of the way, we can connect to G‑d in the fullest way possible.

This is why G‑d made His blessings dependent especially on our observance of these types of commandments. When we empty ourselves of our ego, we can view G‑d’s rewards not as the motivation for complying with His will, but as intrinsic components of our relationship with Him. G‑d is absolute goodness, so when we relate to Him without the interference of our egos, we can experience His goodness purely, as His self-revelation to us.1