Origen to Africanus, a beloved brother in God the Father, through Jesus Christ, His holy Child, greeting. Your letter, from which I learn what you think of the Susanna in the Book of Daniel, which is used in the Churches, although apparently somewhat short, presents in its few words many problems, each of which demands no common treatment, but such as oversteps the character of a letter, and reaches the limits of a discourse. And I, when I consider, as best I can, the measure of my intellect, that I may know myself, am aware that I am wanting in the accuracy necessary to reply to your letter; and that the more, that the few days I have spent in Nicomedia have been far from sufficient to send you an answer to all your demands and queries even after the fashion of the present epistle. Wherefore pardon my little ability, and the little time I had, and read this letter with all indulgence, supplying anything I may omit.
Source: Origen to Africanus (New Advent)