Being destined for the rabbinate, he was taught Hebrew, as well as German and French; and he received instruction in Latin from the minister of his native town.

Here also he acquired Neo-Persian and Turkish, and, save for a short interruption occasioned by a visit to Europe, he remained in Egypt till March 1835.

Weil purposed to give a philologically exact version, which would have been highly desirable in many respects; but the Stuttgart publisher authorized August Lewald to change many objectionable passages, and thus made of it a popular and salable work.

Weil's second great work was Mohammed, der Prophet (Stuttgart, 1843), a life of Mohammed.in the compilation of which he was the first to go back to the oldest accessible sources in Europe.

While pursuing these studies Weil published his Historisch-Kritische Einleitung in den Koran (Bielefeld and Leipsic, 1844 and 1878) as a supplement to Ullman's translation of the Koran, and the translation of one of the original sources of the biography of Mohammed, Leben Mohammed's nach Muhammed ibn Isḥaḳ, Bearbeitet von Abd el-Malik ibn Hischâm (Stuttgart, 2 vols., 1864).

To these must be added Biblische Legenden der Mohammedaner (Frankfurt, 1845), in which Weil argues the influence of the rabbinic legends upon the religion of Islam.

This was followed by the Geschichte der Islamischen Völker von Mohammed bis zur Zeit des Sultans Selim.