To give some historical context, Shadal lived at a time when modern movements were emerging in Germany and corresponded with the leaders of these movements, rabbis like Abraham Geiger (Reform) and Samson Raphael Hirsch (neo-Orthodox). His academic career began as Rationalism was giving way to Romanticism, the belief that one must not put all of one’s faith in reason. Luzatto didn't reject rationalism. However, he believed that the Torah wasn't given primarily to teach us how to think but how to act. He preceded the leading Zionists like Pinsker, Ben Yehudah, and Herzl, and yet he believed that Jews should have a national homeland, taught his classes at the Padua Rabbinical College in Hebrew, and dedicated himself to the revival of literary Hebrew.
Luzatto was religiously observant, possessed a deep faith in God, and believed that the entire Torah was divine. He rejected the assumptions and arguments of Higher Biblical Criticism, a theory formulated by Christian German scholars of his day that argued that the Torah was the product of multiple human authors. At the same time, his academic research led him to also reject the attribution of the Zohar to Rabbi Shimon Bar Yochai nor the authorship of the Book of Ecclesiastes to King Solomon.
Living in 19th century northern Italy (born in Trieste and adult life in Padua), Luzatto was part of a Jewish world where openness to secular culture and ideas was normative. In his commentary to the Tanach, he cites the comments of over 200 individuals. Not only did he rely upon classical Jewish biblical commentaries (e.g. Rashi, Ibn Ezra, Radak, Nachamnides), but he learned from and argued with a wide range of Christian commentators, authors, and philologists whom he cited regularly by name.
Shadal was a child prodigy who gained mastery of Tanach, Talmud, and Midrash at an early age from his father who homeschooled him. His father regularly encouraged young Shmuel to grapple with the text on his own before looking at any commentary. He completed the study of the entire Talmud by age 18. An autodidact, he learned ancient Semitic languages as well as Latin, German, French, and Arabic, all of which gave him access to a wide range of non-Jewish sources. He was a true renaissance man who, besides writing commentaries on the Tanach, siddur, and machzor, published many books, composed poetry, and wrote hundreds of essays, letters, and articles in Italian and Hebrew.
His literary output was remarkable compared to even tenured professors at today’s universities. But his accomplishments were even more stunning in that he lived a Jobian life of tragedies (two of his brothers, most of his eight children, and his first and second wife died during his lifetime); he suffered from chronic illnesses and lived most of his life in poverty.
Shadal addressed questions that we would consider relevant even today such as the relationship between science and the creation story in Genesis Chapter 1 (see below).
יבינו המשכילים כי המכוון בתורה אינו הודעת החכמות הטבעיות, ולא ניתנה התורה אלא להיישיר בני אדם בדרך צדקה ומשפט, ולקיים בלבם אמונת היחוד וההשגחה, כי לא לחכמים לבדם ניתנה תורה, אלא לכל העם.
וכמו שענין ההשגחה והגמול לא נתבאר (ולא היה ראוי שיתבאר) בתורה בדרך פילוסופי, אבל דיברה תורה עליו כלשון בני אדם, כן עניין הבריאה איננו מסופר (ולא היה ראוי שיסופר) בתורה בדרך פילוסופי....
לפיכך אין ראוי לתורני להוציא הכתובים ממשמעותם כדי להסכימם עם החכמות הטבעיות, גם אין ראוי לחוקר שיכחיש בתורה מן השמים, אם ימצא בסיפוריה דברים בלתי מסכימים עם המחקר הטבעי.
והנה רצה ה' להודיע לבני אדם אחדות העולם ואחדות המין האנושי; כי הטעות בשני הענינים האלה גרמה בימי קדם רעות גדולות.
כי מהעדר ידיעת אחדות העולם נמשך, שהיו בני אדם מאמינים מציאות אלהים פרטיים בעלי חסרון ומידות גרועות, והיו עושים מעשים רעים כדי להיות לרצון לפניהם (עיין מה שכתבתי בפרשת יתרו (שמות כ' ג') בפסוק לא יהיה לך).
ומהעדר ידיעת אחדות המין האנושי נמשך, שהיו בני אומה אחת שונאים ומואסים בני אומה אחרת, והיו נוהגים עמהם בכח הזרוע, ולא במשפט ובצדקה.
ושני העיקרים האלה (אחדות העולם ואחדות המין האנושי) הם המכוון הכללי בסיפור מעשה בראשית, ופרטי הספר כוללים עוד כוונות אחרות כאשר יתבאר.
The enlightened ones will understand that the intent of the Torah is not to inform about the natural sciences; and that the Torah was not given except to direct people on the path of righteousness and justice, and to establish in their hearts the belief in [God's] unity and providence, since the Torah was not only given to sages but [rather] to the whole people.
And just like the matter of providence and reward is not explained (and it would not have been fitting that it be explained) in a philosophical manner, but the Torah [rather] spoke about in ways that ordinary people could understand....; so too, the matter of creation is not told (and it is not fitting that it would be told) in the Torah in a philosophical manner....
Therefore, it is not fitting for people loyal to the Torah to distort the meaning of the Torah in an effort to align verses in the Torah with the natural sciences. Similarly, it is not appropriate for those who take a more scholarly approach to the study of the Torah to reject the divine nature of Torah if they find a contradiction between stories in the Torah and scientific research.
And behold (the point of the description of creation in Genesis 1:1), God wanted to inform people of the unity of the [universe] and the unity of the human species; since error in both of these matters (the unity of the world and the unity of humanity) caused great evils in ancient times.
From the lack of awareness of the unity of the [universe], people believe in the existence of specific gods, with defects and inferior character traits; and they would do evil acts in order to please [these gods] (see Shadal on Exodus 20:3).
And from the lack of awareness of the unity of the human species, people of one nation hate and revile the people of another nation and act towards them with the force of arms, and not with justice and righteousness.
And these two fundamental principles (the unity of the [universe] and the unity of mankind) are the main point of the stories of the creation saga; and details of the book also teach other important lessons, as will be explained.
- The purpose of Torah is not to teach science or philosophy. Science teaches science. Philosophy teaches philosophy. The Torah teaches how to live a just and righteous life.
- Genesis Chapter 1 is meant, therefore, not to teach how the universe was created. That is the purview of science. It is meant to teach a moral lesson, namely, that all humanity shares one ancestor who was created in the image of God.
- Missing the latter point--the oneness of God and the oneness of humanity--is dangerous for humanity. When people believe in their own gods who act on their singular whims, the result is disunity. Judaism believes in one God who created and loves all humanity. The belief in one God who professes one morality is meant to foster the sense of commonality and harmony among nations.
- Ultimately for Shadal, Torah is meant to teach morality, and we see this from the first verse in the Torah.
כי ממנו תאכל ואותו לא תכרת:
קלעריקוס והכורם פירשו אל תכרתהו, כי אולי תצטרך לו, כי יארכו ימי המצור ויחסר הלחם לאנשי המלחמה, ויצטרכו לפירות האילנות ודון יצחק ור"ע ספורנו ובעל מנחה בלולה פירשו כי ממנו תאכל כשתלכוד העיר, לכך לא טוב לך להשחיתו.
ולדעתי לא לכך ניתנה תורה, כדי ללמד לבני אדם לעשות חשבונות להנאת עצמם, אבל בהפך לכך ניתנה, לחזק בלבותינו החמלה והחנינה המתנגדות לתועלתנו.
גם פילון וגם יוסף פלאויוס פירשו המצוה הזאת מצד החמלה והרחמים והרחקת האכזריות. ואשר אני אחזה לי הוא כי עיקר המצוה הוא שלא יכרות העץ אחר שאכל מפירותיו, וזה אמנם כדי להרחיק את האדם ממדת כפוי טובה, ולהרגילו שיאהב את המיטיב לו, ולא ישליכנו אחר גוו בזמן שלא יקוה ממנו עוד תועלת.
Deuteronomy 20:19 states that "When in your war against a city you have to besiege it a long time in order to capture it, you must not destroy its trees, wielding the ax against them. You may eat of them, but you must not cut them down. Are trees of the field human to withdraw before you into the besieged city?"
Johannes Clericus (a Christian commentator from 17-18th century Amsterdam) and Naphtali Herz Homberg (18-19th centurey author of the commentary on the Torah called Korem) explained the reason for the obligation "you must not cut them down" is that one may need those trees sometime in the future. The siege may last a long time and bread for the soldiers will be in short supply, and they will need fruit from trees. Don Isaac Abarvanel and Rabbi Ovadia Seforno and Rabbi Avraham Menachem Yakov Hakohen Rappaport (a 16th century Italian rabbi and physician) explain "you may eat of them" to refer to the time when the city has been conquered, and that is why it is not good to cut them down.
However, in my opinion, these utilitarian and self-serving reasons are not what the Torah was given to teach. Rather, the opposite is the Torah's purpose--to strengthen in our hearts a sense of compassion and mercy when it goes against our self-interest.
Both Philo and Josephus understood this commandment in terms of compassion, mercy, and avoiding cruelty. To me it seems that the essence of this commandment not to cut down the tree after having eaten of its fruits is so that we don't develop a habit of being ungrateful, but instead appreciate everyone and anything that does good for us, and to not disregard that which no longer brings us a benefit.
Yet, for nearly 150 years after his death, which occurred on Erev Yom Kippur, Luzatto's commentary seemed not to attract much attention. One reason may be that Shadal was an academic and, unlike his contemporary Samson Raphael Hirsch with Shadal shared much in common, he viewed his primary role as a professor and scholar, not a communal rabbi. As an academic, he had only a few dozen students. Relatedly, the Jewish world seems commonly divided into two groups, Ashkenazim and Sephardim, and Italian Jewry was both had unique features that didn't fit neatly into one of those categories and was, therefore, largely ignored by the Jewish world.
Lastly, Shadal was too religious for the pure academics who saw little of value in traditional Judaism and too scholarly for the religious who believed that a verse in the Torah said what classical Jewish commentators said it meant. However, for those who believe as Shadal did כי האמת לבדה היא מגמתי ואמונתנו תהילה לאל איננה מפחדת מן האמת , "for truth alone is my goal, and our religion, which glorifies God, is not afraid of the truth" (page 23, in Bassi's edition Shadal's Introduction to his commentary on Isaiah), they will come to see his commentary to be a invaluable treasure.