Or HaChaim on Leviticus 26:18/אור החיים על ויקרא כ״ו:י״ח

1 לא תשמעו לי, "you do not listen to Me." Teshuvah is made conditional on "listening" to G'd, i.e. studying Torah. True repentance is impossible without Torah study.

2שבע על חטאתיכם "sevenfold for your sins." The Torah does not mean that G'd will exact seven retributions for each sin but that G'd will exact retribution for the sins of the Jewish people which number seven. The punishment will fit the crime both qualitatively and quantitatively. The seven sins consist of the following: 1) failure to listen; 2) failure to perform; 3) relating to the statutes with disdain; 4) loathing of G'd's social laws; 5) preventing others from performing the commandments; 6) breaking G'd's covenant; 7) remaining unaffected by G'd's penalties and thereby closing the gates of repentance. This explains what the sages meant when they said in Rosh Hashanah 16 that three books are open in front of G'd on New Year's Day; one contains the names of the totally wicked; one contains the names of the totally righteous, and one contains the names of the "average" people (the ones whose merits and demerits are in balance). The latter are given until the Day of Atonement to see if they will repent. If they fail to do so they will automatically be inscribed in the book of the confirmed sinners.