Imitation of Christ

Multam possumus pacem habere, si volumus nos cum aliorum dictis et factis quæ ad nostram curam non spectant non occupare. Quomodo potest ille in pace die permanere, qui alienis curis se intermiscet, qui occasiones forinsecus quærit, qui parum vel raro se intrinsecur colligit? Beati simplices, quoniam multam pacem habebunt.
 

We may enjoy abundance of peace if we refrain from busying ourselves with the sayings and doings of others, and things which concern not ourselves. How can he abide long in peace who occupies himself with other men's matters, and with things without himself, and meanwhile pays little or rare heed to the self within? Blessed are the uncomplicated, for they shall have abundance of peace.

Imitation of Christ, I, 11:1