The Adornment of the Spiritual Marriage, by Jan van Ruysbroeck, , at sacred-texts.com
From inward gratitude and praise there arises a two fold grief of the heart and torment of desire. The first grief is, that we feel ourselves to lag behind in thanking, praising, glorifying and serving God. The second is, that we do not grow in charity, in virtue, in faith, and in perfect behaviour as much as we desire, that we may become worthy to thank and praise and serve God as it is proper to do. This is the second grief. These two are root and fruit, beginning and end, of all inward virtues.
Inward grief and pain for our shortcomings in virtue and the praise of God, is the highest effect of this first degree of the inward exercise; and by it this degree is perfectly achieved.