Lamentations 2:18

The Savior also wept over the city of Jerusalem because its inhabitants had not repented; and Peter washed out his triple denial with bitter tears, thus fulfilling the words of the prophet: "rivers of waters run down my eyes." Jeremiah too laments over his impenitent people, saying, "O that my head were waters and my eyes a fountain of tears, that I might weep day and night for … my people!" And farther on he gives a reason for his lamentation: "do not weep for the dead," he writes, "neither bemoan him, but weep bitterly for him that goes away, for he shall return no more." The Jew and the Gentile therefore are not to be bemoaned, for they have never been in the church and have died once for all (it is of these that the Savior says, "Let the dead bury their dead"15); weep rather for those who by reason of their crimes and sins go away from the church and who, suffering condemnation for their faults, shall no more return to it. It is in this sense that the prophet speaks to ministers of the church, calling them its walls and towers and saying to each in turn, "O wall, let tears run down." In this way, it is prophetically implied, you will fulfill the apostolic precept: "Rejoice with them that rejoice and weep with them that weep." By your tears you will melt the hard hearts of sinners until they too weep. However, if they persist in evildoing they will find these words applied to them: "I … planted for you a noble vine, wholly a right seed; how then are you turned into the degenerate plant of a strange vine to me?" He says again, "saying to a stock, you are my father; and to a stone, you have brought me forth; for they have turned their back to me, and not their face." He means they would not turn toward God in penitence but in the hardness of their hearts turned their backs on him to insult him. […]

Not every kind of shedding of tears is produced by one feeling or one virtue. For in one way does that weeping originate that is caused by the pricks of our sins striking our heart, of which we read, "I have labored in my groaning, every night I will wash my bed; I will water my couch with my tears." And again, "Let tears run down like a torrent day and night; give yourself no rest, and do not let the apple of your eye cease." In another, that which arises from the contemplation of eternal good things and the desire of that future glory, owing to which even richer well-springs of tears burst forth from uncontrollable delights and boundless exultation, while our soul is thirsty for the mighty living God, saying, "When shall I come and appear before the presence of God? My tears have been my meat day and night," declaring with daily crying and lamentation, "Woe is me that my sojourning is prolonged," and, "Too long has my soul been a sojourner."In another way do the tears flow forth, which without any conscience of deadly sin yet still proceed from the fear of hell and the recollection of that terrible judgment, with the terror of which the prophet was smitten and prayed to God, saying, "Enter not into judgment with your servant, for in your sight shall no one living be justified." There is too another kind of tears, which are caused not by knowledge of one's self but by the hardness and sins of others; whereby Samuel is described as having wept for Saul. Both the Lord in the Gospel and Jeremiah in former days wept for the city of Jerusalem, the latter thus saying, "O, that my head were water and my eyes a fountain of tears! […]

From these tears those are vastly different that are squeezed out from dry eyes while the heart is hard, and although we cannot believe that these are altogether fruitless (for the attempt to shed them is made with a good intention, especially by those who have not yet been able to attain to perfect knowledge or to be thoroughly cleansed from the stains of past or present sins), yet certainly the flow of tears ought not to be thus forced out by those who have already advanced to the love of virtue, nor should the weeping of the outward person be with great labor attempted, as even if it is produced it will never attain the rich copiousness of spontaneous tears. For it will rather cast down the soul of the suppliant by his endeavors, and humiliate him, and plunge him in human affairs and draw him away from the celestial heights, wherein the awed mind of one who prays should be steadfastly fixed, and will force it to relax its hold on its prayers and grow sick from barren and forced tears.

Here one turns toward seeking divine justice through prayer. First, one is invited to pray, second to consider the prayer itself. As Verse 20 says: "Look, O Lord, and see! With whom hast thou dealt thus?" Regarding an invitation to pray, two notions are proposed. …

Their heart cried unto the Lord,....