 Beginning with 1810, he, as a rich and influential merchant, was entrusted, together with Abraham Prinz and Solomon Reuben, with the responsibility of forwarding to Palestine the contributions which were sent annually to Amsterdam.In 1822 he ruled that in future only one representative, instead of two, should be sent from Palestine for both the Sephardic and the Ashkenazic congregations, and that the money collected for the Ḥaluḳḳah should be divided in proportion to the number of persons in the Palestinian congregations in question.When, in 1829, the congregation of the Ashkenazim in Jerusalem had become involved in financial difficulties through the building of a new synagogue and school, and was obliged to appeal for support to its coreligionists in Europe, Lehren, as president of the Ḥaluḳḳah committee, prohibited in a harshly-worded circular the transmission of any further contributions to Jerusalem.