4 Listen, august Emperor. I cannot deny that you have a zeal for the faith; I do confess that you have the fear of God. But you have a natural vehemence, which, if any one endeavours to soothe, you quickly turn to mercy; if any one stirs it up, you rouse it so much more that you can scarcely restrain it. Would that if no one soothe it, at least no one may inflame it! To yourself I willingly entrust it, you restrain yourself, and overcome your natural vehemence by the love of piety.
Source: Letters (New Advent)