1 Neither must this multitude's throng be defrauded, nor their infirmity burthened. Silence we ask, and quiet, in order that our voice, after yesterday's labour, be able with some little vigour to last out. It must be believed, that your love has met together in greater numbers today for nothing else, but that you may pray for those whom an alien and perverse inclination does keep away. For we are speaking neither of heathens nor of Jews, but of Christians: nor of those that are yet Catechumens, but of many that are even baptized, from the Laver of whom you do no wise differ, and yet to their heart you are unlike.
For today how many brethren of ours we think of, and deplore their going unto vanities and lying insanities, to the neglect of that to which they have been called. Who, if in the very circus from any cause they chance to be startled, do immediately cross themselves, and stand bearing It on the forehead, in the very place, from whence they had withdrawn, if they had borne It in heart. God's mercy must be implored, that He may give understanding for condemning these things, inclination to flee them, and mercy to forgive.
Opportunately, then, of Penitence a Psalm today has been chanted. Speak we even with the absent: there will be to them for our voice your memory. Neglect not the wounded and feeble, but that you may more easily make whole, whole ye ought to abide. Correct by reproving, comfort by addressing, set an example by living well, He will be with them that has been with you. For now that you have overpassed these dangers, the fountain of God's mercy is not closed. Where you have come they will come; where you have passed they will pass.
A grievous thing it is indeed, and exceeding perilous, nay ruinous, and for certain a deadly thing, that witting they sin. For in one way to these vanities does he run that despises the voice of Christ; in another way, he that knows from what he is fleeing. But that not even of such men we ought to despair, this Psalm does show.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)