Lev at first planned the compilation of a work in the manner of the Beit Yosef of R. Joseph Caro. When in 1551 the Beit Yosef was published he forbade its use out of fear that it would lead to a decrease in the study of the Talmud. However, when on one occasion he could not remember one of the sources of the Arba'ah Turim and found it in the Beit Yosef, he changed his attitude and realized the value of the work. His responsa, in four parts, were first published separately but then together in Amsterdam in 1726. A new edition of the responsa in two volumes appeared in Jerusalem in 1959/60. Lev attributes many glosses to his son David out of a desire to perpetuate his memory, but it is probable that he himself was the author of most of them. He was highly thought of by contemporary scholars.