3 What men should beware of, we have said; but what if they shall have fallen they should imitate, let us hear. For many men will to fall with David, and will not to rise with David. Not then for falling is the example set forth, but if you shall have fallen for rising again. Take heed lest you fall. Not the delight of the younger be the lapse of the elder, but be the fall of the elder the dread of the younger. For this it was set forth, for this was written, for this in the Church often read and chanted: let them hear that have not fallen, lest they fall; let them hear that have fallen, that they may rise.
So great a man's sin is not hushed, is proclaimed in the Church. There men hear that are ill hearers, and seek for themselves countenance for sinning: they look out for means whereby they may defend what they have made ready to commit, not how they may beware of what they have not committed, and they say to themselves, If David, why not I too? Thence that soul is more unrighteous, which, forasmuch as it has done it because David did, therefore has done worse than David. I will say this very thing, if I shall be able, more plainly.
David had set forth to himself none for a precedent as you have: he had fallen by lapse of concupiscence, not by the countenance of holiness: thou dost set before your eyes as it were a holy man, in order that you may sin: thou dost not copy his holiness, but dost copy his fall. Thou dost love that in David, which in himself David hated: you make you ready to sin, you incline to sin: in order that you may sin you consult the book of God: the Scriptures of God for this you hear, that you may do what displeases God.
This did not David; he was reproved by a Prophet, he stumbled not over a Prophet. But others hearing to their health, by the fall of a strong man measure their weakness: and desiring to avoid what God condemns, from careless looking do restrain their eyes. Them they fix not upon the beauty of another's flesh, nor make themselves careless with perverse simpleness; they say not, “With good intent I have observed, of kindness I have observed, of charity I have long looked.” For they set before themselves the fall of David, and they see that this great man for this purpose has fallen, in order that little men may not be willing to look on that whereby they may fall.
For they restrain their eyes from wantonness, not readily do they join themselves in company, they do not mingle with strange women, they raise not complying eyes to strange balconies, to strange terraces. For from afar David saw her with whom he was captivated. Woman afar, lust near. What he saw was elsewhere, in himself that whereby he fell. This weakness of the flesh must be therefore minded, the words of the Apostle recollected, “Let not sin therefore reign in your mortal body.” He has not said, let there not be; but, “let there not reign.”
There is sin in you, when you take pleasure; there reigns, if you shall have consented. Carnal pleasure, especially if proceeding unto unlawful and strange objects, is to be bridled, not let loose: by government to be tamed, not to be set up for government. Look and be without care, if you have nothing whereby you may be moved. But you make answer, “I contain with strong resolution.” Are you any wise stronger than David?
Source: The Enarrations, or Expositions, on the Psalms (New Advent)