The first book of the Ethicon of Gregory Barhebraeus (d. 1286) contains a description of a number of ascetical practices such as the manner of saying prayers, reading spiritual books, reciting psalms, fasting, living in seclusion, pilgrimage, etc.. Barhebraeus' description is partly based on Greek and Syriac authors on the spiritual life. The originality of the work, however, lies in it being influenced by Islamic authors such as Al-Ghazali and B. Sina. This influence causes Barhebraeus to pay attention to basically Islamic concepts as samâ, dhikr, etc.

Much attention is given to the identification of the sources. In a special appendix one finds the parallel texts of Al-Ghazali's Ilhyâ 'ulûm aldîn and the first book of Barhebraeus' Ethicon.