Besides the Rambam, the Ramban was probably the greatest and most influential of the Rishonim. Born in Gerona, he remained there most of his life. Like the Rambam, he was equally distinguished in both Halacha and Hashkafa. His contributions to scholarship covered every area: his Talmudic commentaries combined the French school of analysis with the Spanish emphasis on halacha and every word he wrote was scrupulously examined in all of Spain; he wrote major works defending Alfasi against the critique of Baal HaMaor and Ravad and Bahag against Rambam’s criticisms of his classification of mitzvos; he wrote masterful works of halacha such as Toras HaAdam on the laws of death and mourning including a philosophical section, Shaar HaGmul; he committed to writing derashos he had given on fundamental topics such a Rosh Hashana, Koheles and Torah; he wrote an account of his public disputation in Barcelona with the convert Pablo Christiani in j1263; he composed poetry, but probably the most popular of his works is the Commentary on Chumash which he modestly directed to “calm the minds of those weary of galus, studying on Shabbos and Moadim”.
The Commentary is multi-dimensional including all methods of interpretation from simple pshat to esoteric Kabbala. The Ramban is not satisfied with explaining the verse at hand; he is concerned with the overall structure of the various chapters and their interconnections. Many of his explanations have become basic principles of Judaism. The Commentary is available in English translation.
The Ramban held that the mitzva of settling Eretz Yisrael applies even today and ultimately settled there himself during the last years of his life. When he arrived in Jerusalem there was hardly a minyan and he wrote that “what had been the most sacred is now the most desecrated”. He organized a minyan and erected a synagogue.
Over the centuries his view on the mitzvah of settling the Land has been most influential. He also held that even mitzvos which were obligatory outside of the Holy Land did not achieve the level of shleimus as when performed within Eretz Yisrael. Looking back at the chaotic state of the Land during the periods of non-Jewish control, he interpreted Leviticus 26:32 as promising that Israel’s enemies will be unable to settle the Land. As part of the mitzva of settling the Land he included the admonition “that we not forsake the Land to others of the nations” (Numbers 33:53).
Recognizing the anguish people experience in everyday life without apparent explanation, he composed a major Commentary on the Book of Job.