“Holy Mother the Church celebrates today a feast of the Exultation of the Holy Cross, which we honor twice in the year. The first is the Discovery, in the month of May (May 3). The second today (Sept. 14) on the Exultation. Reason, because after the Holy Cross was discovered by St. Helena, it came into the possession of the infidels, who contemptuously held it. But Heraclius, the Most Holy and Christian Roman Emperor, extracted it from the possession of the infidels and exalted it honorably, and today is the feast of that exaltation. So that our words be fruitful, let us now say the Hail Mary.
It is a common Catholic doctrine of sacred theology that although Christ had other innumerable ways of redeeming and saving mankind, he nevertheless chose to save us through his cross, and to redeem obedient and believers for himself. St. Thomas in his (Summa theologiae) III, q. 46, a. 4, assigns seven reasons why this was fitting. I shall speak of one, the second, as an introduction of this material to you.
This reason is, because when satisfaction needs to be made for some sin, it is reasonable that the satisfaction correspond to the sin. For example, if someone sins against God or neighbor by thinking evil in his heart, or by speaking evil, or doing bad things, for such a person to make fitting satisfaction (condigne satisfacere), he ought to take on pain in the heart from this sin, and to strike his heart. If one sins by mouth by defaming or swearing, proper satisfaction ought not only to be confessed by mouth but he should also to seek pardon from God and neighbor by mouth, if he offended him. Therefore if through the eyes you have sinned by gazing etc. proper satisfaction is to weep, etc. Also if you have sinned by ears, by listening to evil things about a neighbor, healing is made by hearing mass and sermons etc. If through taste, by breaking the fast of the church, etc., to abstain, and so the satisfaction corresponds to the offense. If you have sinned by hand, extend it in prayer. If you have shed blood, the proper penitence is to shed your own blood by the discipline. So it says in Genesis 9: “Whosoever shall shed man’s blood, his blood shall be shed.” (v. 6). If you have sinned by the body through carnal sins, you ought to wear a hair shirt (cilicium). See how appropriate satisfaction is made when the penalty corresponds to the offense. Scriptural proof if taken from that which [Christ, in fact John the Baptist] said in Luke 3 “Bring forth therefore fruits worthy of penance,” (v. 8). The fruits of penance are worthy when they correspond to the offense.”  St. Vincent Ferrer