Now we can explain what it says later in the Parsha [26-14]:
"וְאִם לֹא תִשְׁמְעוּ לִי וְלֹא תַעֲשׂוּ אֵת כָּל הַמִּצְוֹת הָאֵלֶּה"
ואם לא תשמעו לי – להיות עמלים בתורה לדעת מדרש חכמים, יכול לקיום המצות, כשהוא אומר ולא תעשו וגו׳, הרי המצות אמורים, הא מה אני מקיים ואם לא תשמעו לי, להיות עמלים בתורה.
BUT IF YOU WILL NOT HEARKEN UNTO ME to study the Torah laboriously in order to fathom the textual interpretation of the Sages…, I also will do this unto you, etc. One might think that this refers to the fulfillment of the commandments! When, however, Scripture states immediately afterwards: "and you will not do [all my commandments]", it is evident that the fulfillment of the commandments is mentioned there! How, then, must I explain לא תשמעו לי? Obviously as meaning: "But if you will not hearken unto Me to study the Torah industriously" as I bid you do when I said אם בחקתי תלכו.
Rashi strangely enough contradicted himself. First he mentioned "להיות עמלים בתורה" - to toil [industriously] in Torah. That corresponds to what he said earlier to explain אם בחקתי תלכו as meaning that you have to toil in Torah. To get the blessing we have to toil in Torah. The curse [in this pasuk] comes when we don't. Then he added that we have to know "מדרש חכמים" - the textual interpretations of the Sages. What does THAT have to do with anything? That is different than toiling in Torah. Then Rashi continues and says:
"הא מה אני מקיים 'ואם לא תשמעו לי' - להיות עמלים בתורה.
Back to עמלים בתורה with the part about "מדרש חכמים"?
Later in pasuk ט"ו, Rashi says:
When referring to the first sin, he says "לא למד". The issue is not that they didn't learn but that they didn't TOIL. So Rashi should have said "לא עמל"?
