Pride and other sins

In order to overcome pride, God punishes certain men by allowing them to fall into sins of the flesh which though they be less grievous are more evidently shameful…From this indeed, the gravity of pride is made manifest. For just as a wise physician in order to cure a worse disease allows the patient to contract one that is less dangerous, so the sin of pride is shown to be more grievous by the very fact that as a remedy, God allows men to fall into other sins.

St Thomas Aquinas, the Summa, quoted by Peter Kreeft in For Heaven’s Sake, pg 96.

And some who are the most gifted in the things of God will stumble in those days and fall, but this will only refine and cleanse them and make them pure until the final end of all their trials at God's appointed time (Daniel 11:34 TLB)