From today’s BOC Reading from Treasury:

There can be no true conversion or contrition where mortifying the flesh and good fruits do not follow. True terrors and sorrows of the soul do not permit the indulgence of the body in lusts, and true faith is not ungrateful to God or contemptuous of his commandments. In a word, there is no penitence inwardly which does not produce outwardly the punishing of the flesh. (Ap. XII:131)

We believe that God’s glory and command require penitence to produce good fruits, and that good fruits like true fasting, prayer, and charity have his command. (Ap. XII:139)