Leviticus 26:14

ואם לא תשמעו לי BUT IF YE 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 ye will not do [all my commandments]”, it is evident that the fulfilment 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 (cf. Rashi on v. 3). And what is the force of the word לי? (To express this idea would it not have sufficed to state: ואם לא תשמעו?) It implies that your disobedience is directed לי against Me. The word לי is used only in the case of such a one who knows his Master and yet of set purpose rebels against Him (i. e. the entire chapter containing these threats of punishment is addressed only to such a person, not to one who sins against God unwittingly). Similarly in reference to Nimrod: (Genesis 10:9) “a mighty hunter before (לפני) the Lord” which means that he knew Him and yet of set purpose rebelled against him. Similarly in reference to the men of Sodom: (Genesis 13:13) “[But the men of Sodom were] evil and sinful against the Lord ('לה‎) exceedingly” — they knew their Master and yet of set purpose rebelled against him (Sifra, Bechukotai, Section 2 1-2; cf. Rashi on those two verses). ולא תעשו AND YOU WILL NOT DO — Because you will not learn you will not practice the commandments: thus you have two separate sins mentioned here (Sifra, Bechukotai, Section 2 3).

But if you will not hearken to me, and will not do all these commands:

וְאִם־לֹ֥א תִשְׁמְע֖וּ לִ֑י וְלֹ֣א תַעֲשׂ֔וּ אֵ֥ת כׇּל־הַמִּצְוֺ֖ת הָאֵֽלֶּה׃