he wrote an account of the 1655 conference at whitehall, at which manasseh ben israel put a case to the parliamentary government of oliver cromwell, to lift the restrictions on jews living in england. he was in correspondence with manasseh, was an "enthusiastic student of hebrew and aramaic" and philo-semite. in lobbying for the rights of the jews to official readmission to the country, and in high expectations from this, jessey was an associate of john dury and nathaniel holmes. in 1658 jessey composed a work entitled "an information concerning the present state of the jewish nation in europe and judea". he both advocated the conversion of the jews and treating them with kindness, and believed god's special concern for them. the pamphlet also expresses concern for the trials of the jews in palestine, specifically the suffering from the lack of donations following the khmelnytsky uprising which had led to a decrease in the jewish population in eastern europe and a subsequent loss of donations. as well as raising money for the impoverished jews of palestine, jessey was also well acquainted with two of the key figures disseminating information throughout europe about the jewish millenarian prophet sabbatai zevi.