Tristitia est utilis quia aliquid fugiendum, non quia sit secundum se malum, sed quia est occasio mali: dum vel homo nimis inhaeret ei per amorem, vel etiam ex hoc praecipitatur in aliquod malum, sicut patet in bonis temporalibus.
Sadness is useful because a thing is to be avoided, not as though it were evil in itself, but because it is an occasion of evil: either through one's being attached to it, and loving it too much, or through one's being thrown headlong thereby into an evil, as is evident in the case of temporal goods.
Et secundum hoc, tristitia de bonis temporalibus potest esse utilis; sicut dicitur Eccle. VII, "melius est ire ad domum luctus, quam ad domum convivii: in illa enim finis cunctorum admonetur hominum".
And, in this respect, sadness for temporal goods may be useful; according to Ecclesiastes 7:3: "It is better to go to the house of mourning, than to the house of feasting: for in that we are put in mind of the end of all."
Sicut dicitur Eccle. VII, "cor sapientum ubi tristitia, et cor stultorum ubi laetitia".
According to Ecclesiastes 7:5, "the heart of the wise is where there is sadness, and the heart of fools where there is mirth".