Commento su Deuteronomio 30:20

ולדבקה בו, meaning that all of your activities during life on earth should be focused on giving glory to His name.

לאהבה את ה׳ אלוקיך, "to love the Lord your G'd, etc." This passage is a continuation of the thoughts in verse 19 "in order that you may live, you and your offspring." The purpose of this desire for life on this earth must be to learn to love G'd and to obey His commandments. When Moses concludes: "for He is your life, etc." Moses merely reflects that there cannot be a meaningful purpose in life on earth other than to cleave to G'd to the best of our abilities. This makes our life in this world a fitting prelude to our life in the celestial spheres., i.e. ארך ימים.

To obey Him. This refers to the in depth study and toil in Torah.

V. 20. לאהבה וגו׳, und nochmals fasst Mosche den Begriff dieses "Lebens" in der Liebe Gottes zusammen, die nichts anderes will, als: Gott zu gehorchen und in Freud und in Leid, in Leben und Sterben fest und innig mit Ihm verbunden zu bleiben. Dieses "Gott lieben" bildet unser Leben und unser Glück, כי הוא חייך וארך ימיך וגו׳. Diese ihre Befriedigung in sich selbst findende Liebe spricht sich in Nedarim 62 a in praktischer Betätigung also aus: עשה דברים לשם פועלם ודבר בהם לשמם אל תעשם עטרה להתגדל בהם ואל תעשם קורדום לעדור בן, erfülle die Lebensaufgaben um ihres Gebers willen, rede von ihnen um ihrer selbst willen, mache sie nicht zu einem Kranze, dich zu verherrlichen, noch zu einem Spaten, damit zu graben.

כי הוא חייך, “for He is your life;” a reference to Hashem.

כי הוא חייך, for your cleaving to Him is your real life, the reason why you will enjoy eternal life;

To cling to Him: One who is unable to learn Torah should at least try to attain the love of Hashem through clinging to Him. This is explained in the Gemara (Kesuvos 111) as referring to one who marries his daughter to a Torah scholar, and helps a Torah scholar financially. The Torah considers this as if he is clinging to the Divine Presence. Through joining with, and helping a Torah scholar, he attains a small part of the love of Hashem.

לשבת על האדמה, "to dwell in the land, etc." We have to read this as if the word לשבת had been prefaced with the conjunctive letter ו. Dwelling in the Holy Land is part of the attainment of completeness through performance of all parts of Torah observance. Our sages have so extolled the virtue of dwelling in the Holy Land that they said that anyone who walks in it a distance of four cubits qualifies for a share in the hereafter (Ketuvot 111).

ואורך ימיך לשבת על האדמה, during the transient life on earth, during which through study, serious contemplation of your duties, and your performance of them you will qualify for the life awaiting you in the hereafter. Compare Avot 4,16 where we have been told that life on earth is merely to be viewed as a vestibule to the hereafter, a place in which one makes suitable preparations for eternal life in the Palace.