 It is seen from his "Sefer HaNitzachon" that, besides his rabbinical studies, Lipmann occupied himself with the study of the Bible, that he was acquainted with Karaite literature, that he read the New Testament, and that he knew Latin.His authority in rabbinical matters is shown by his circular to the rabbis warning them against the use of any "shofar" not made of a ram's horn.There are also "responsa" addressed to him by Jacob ben Moses Mölln, and Israel Isserlein mentions him as one of five scholars who met at Erfurt.