Dominica III post Pentecosten: "... true righteousness is merciful, and false righteousness is contemptuous..."

From the Holy Gospel according to Luke
Luke 15:1-5
At that time: the publicans and sinners drew near unto him to hear him. And so on.

Homily by Pope St. Gregory (the Great)
34th on the Gospels
Ye have heard, my brethren, from the Gospel which hath but now been read, how that the publicans and sinners drew near unto our Redeemer, and how that He received them, not only to converse, but also to eat with Him. And when the Pharisees and Scribes saw it, they murmured. From this learn ye, that true righteousness is merciful, and false righteousness is contemptuous, albeit that the righteous also oft-times feel moved with just indignation at sinners. But it is one thing to feel thus indignant through pride, and another to feel so through love of law.

The righteous indeed look down upon sinners, and yet, as not despising them; they abandon them, and yet, as not without hope; they fight against them, and yet, as loving them all the while; for if they be behoven to chasten them grievously as touching the outer man, yet is it through charity which offereth sweetness to their inner man. In their hearts they prefer before themselves them whom they are correcting; they hold as better than themselves them whom they judge. And thus doing, they watch by carefulness over them, which are committed unto their charge, and, by lowly-mindedness, over themselves.

On the other hand, they whose exaltation cometh of a false righteousness, look down upon their neighbour, but are softened by no mercy toward his misery, and are all the more sinful, because they perceive not that they themselves are sinners. Of such were those Pharisees who judged the Lord because He received sinners, and, in the dryness of their own heart, rebuked the very Fountain of mercy. They were sick of so desperate a sickness that they knew not of themselves that they were sick; but, that they might know that they were so, the Heavenly Physician applied to them His tender ointments, and, by means of a gracious parable, lanced the boil of their pride of heart.