The aim of this paper is to present an account of how Christian philosophy develops in its Islamic philosophical and theological context. I will focus on the philosophical thought of Gregory Bar Hebraeus (d. 1286). I will show that Bar Hebraeus attempts to harmonize the Neoplatonic Avicennian ontological theory of good and evil with the ethical theories of his contemporary Islamic philosophical theology (primarily,Ašʿarism) as well as materials taken from Christian sources. From Avicenna, Bar Hebraeus takes the idea the evil is privation. From the Ašʿarites, Bar Hebraeus inherits moral consequentialism and the divine command theory.