Origen of Alexandria : For do not think that the omnipotent God commanded this and consecrated this in the law that incense be brought to him from Arabia. But this is the incense that God seeks to be offered by human beings to him, from which he receives "a pleasing odor," prayers from a pure heart and good conscience in which God truly receives a pleasing warmth. — HOMILIES ON Leviticus 13.5.2