A spirit of mortification, rather than being just an outward show of Love, arises as one of its consequences. If you fail in one of these little proofs, acknowledge that your love for the Love is wavering. (Furrow, 981)
For parents and, in general, for those whose work involves supervision or teaching, penance is to correct whenever it is necessary. This should be done bearing in mind the type of fault committed and the situation of the person who needs to be so helped, not letting oneself be swayed by subjective viewpoints, which are often cowardly and sentimental.
A spirit of penance keeps us from becoming too attached to the vast imaginative blueprints we have made for our future projects, where we have already foreseen our master strokes and brilliant successes. What joy we give to God when we are happy to lay aside our third‑rate painting efforts and let him put in the features and colours of his choice! (Friends of God, 138)