Maristella Botticini and Zvi Eckstein explain how Jewish literacy led to wealth:
Judaism after the year 70, required both children and adults to read and to study the Torah. That is, it was not enough to just read without understanding the text and it was not enough to just memorize the text. This means that after 70, Judaism imposed on its members not just literacy per se but also the duty of understanding what was written. Again, this skill was valuable for occupations that benefited from understanding what was written in a contract or business letter such as crafts, trade or banking.
From the way learning happens even today, we know that if someone learns one language, it is more likely that the same person can learn a second or third or a fourth language. In the period we study (70-1492), Jews read the Torah in Hebrew and learned the different local languages of the locations in which they dwelled (e.g., Aramaic, Greek, Latin, Arabic, Spanish and German).
Acquiring basic literacy was the first step in moving to higher studies and acquiring more and more education. So learning to read and studying the Torah were prerequisites for learning and studying more complex texts such as the Mishna and the Talmud. Those who studied these texts (consisting of extensive debates and discussions among rabbis and sages) acquired the ability to think in an analytical and argumentative way — skills that could become helpful in commercial, entrepreneurial and financial activities.
Literacy and education fostered mobility because literate and educated Jews could more easily migrate to new locations in search of business opportunities, learn the local languages, and stay in touch with relatives and business associates back at home by writing and reading letters. (In chapter 6, we provide a sample of these letters.) Mobility was not an asset for farmers, but it surely was for merchants and traders.
Literacy, education and mobility fostered networking abilities among Jews living in different locations: it is hard to stay connected with business associates if one cannot read and write letters and contracts. Again, networking was not especially valuable for farmers, but it was very valuable for traders and bankers, who could exploit arbitrage opportunities through networking with business associates in different locations, and exchange information and capital when needed.
Literacy and education are prerequisites for having legal codes and courts that can enforce contracts. Even today, having contract-enforcing institutions promotes commercial and trading activities. Many centuries ago, thanks to their literacy and education, the Jews had a set of contract-enforcing institutions, more precisely: a legal written code (the Talmud); the rabbinical courts that ensured that deeds and contracts among Jews could be enforced regardless of where the Jews were living; and the rabbinical written Responsa that helped solve legal controversies when unforeseen in the Talmud.