"im bechukosai teileichu v'es mitsvosai tishmoru va'asisem osam..."
Based upon Toras Kohanim and Rashi an interpretive translation of this verse reads as follows: "if you toil assiduously in studying My Torah in order to observe My commandments and actually fulfill them..." Understood in this vein the pasuk is instructing us that the sine qua non for Klal Yisroel's religious life and observance is not only talmud Torah, but amalah b'Torah. This vital point is well worth underscoring; simple talmud Torah does not suffice, intensive study is required. Such intensity, as Chazal comment elsewhere, involves self-sacrifice. "Ein Torah miskayemes elah b'mi she'meimis atzmo aleha - Torah stays with he who sacrifices his life for it."
The nexus between amalah shel Torah and shmiras haMitzvos should be understood on at least two different levels. On an intellectual level, facile, lackadaisical study virtually guarantees errors. A superficial grasp of halachic concepts or principles is often, to varying degrees, an incorrect grasp. It provides a basis for misguided applications and extrapolations. Truth is not simplistic and thus not casually acquired. And thus, to re-iterate, facile, lackadaisical study virtually guarantees errors. Not surprisingly, study of halachah punctuated with errors yields an equally flawed observance of halachah.
On a religious, experiential level, Torah itself is so profound and holy that it defies measurement or description - "aruka mei'eretz middah..." Such is the reality of Torah. Our perception of Torah, however, is another matter entirely. To us, Torah is only as profound as we perceive it to be. "Ki lo davar rake hu. V'im rake - mikem hu rake - Torah is not something hollow. And if it is hollow, the hollowness is on your account." If rachmanah litslan we study Torah lazily and superficially, we perceive Torah to be flat and superficial. Instead of holiness we experience hollowness. Torah as it is, holy and profound dvar Hashem, inspires scrupulous and alacritous observance. Torah perceived through facile and lackadaisical study discourages such observance.