Catechism of the Council of Trent: Confirmation
The Grace Of Strength
But besides these things, which are common to this and the other (Sacraments), it is peculiar to Confirmation first to perfect the grace of Baptism. For those who have been made Christians by Baptism, still have in some sort the tenderness and softness, as it were, of newborn infants, and afterwards become, by means of the Sacrament of chrism, stronger to resist all the assaults of the world, the flesh and the devil, while their minds are fully confirmed in faith to confess and glorify the name of our Lord Jesus Christ. Hence also originated the very name (Confirmation), as no one will doubt. For the word Confirmation is not derived, as some not less ignorantly than impiously have pretended, from the circumstance that persons baptised in infancy, when arrived at mature years, were of old brought to the Bishop, in order to confirm their faith in Christ, which they had embraced in Baptism, so that Confirmation would seem not to differ from catechetical instruction. Of such a practice no reliable testimony can be adduced. On the contrary, the name has been derived from the fact that by virtue of this Sacrament God confirms in us the work He commenced in Baptism, leading us to the perfection of solid Christian virtue.
Increase In Grace
But not only does it confirm, it also increases (divine grace), as says Melchiades: The Holy Ghost, whose salutary descent upon the waters of Baptism, imparts in the font fullness to the accomplishment of innocence, in Confirmation gives an increase of grace; and not only an increase, but an increase after a wonderful manner. This the Scriptures beautifully express by a metaphor taken from clothing: Stay you in the city, said our Lord and Saviour, speaking of this Sacrament, until you be clothed with power from on high.
If pastors wish to show the divine efficacy of this Sacrament—and this, no doubt, will have great influence in affecting the minds of the faithful—it will be sufficient if they explain what occurred to the Apostles themselves. So weak and timid were they before, and even at the very time of the Passion, that no sooner was our Lord apprehended, than they instantly fled ; and Peter, who had been designated the rock and foundation of the Church, and who had displayed unshaken constancy and exalted magnanimity, terrified at the voice of one weak woman, denied, not once nor twice only, but a third time, that he was a disciple of Jesus Christ; and after the Resurrection they all remained shut up at home for fear of the Jews. But, on the day of Pentecost, so great was the power of the Holy Ghost with which they were all filled that, while they boldly and freely disseminated the Gospel confided to them, not only through Judea, but throughout the world, they thought no greater happiness could await them than that of being accounted worthy to suffer contumely, chains, torments and crucifixion, for the name of Christ.
Character Of Soldier Of Christ
Confirmation has also the effect of impressing a character. Hence, as we before said of Baptism, and as will be more fully explained in its proper place with regard to the Sacrament of Orders also, it can on no account ever be repeated.
If, then, these things be frequently and accurately explained by pastors, it will be almost impossible that the faithful, having known the utility and dignity of this Sacrament, should not use every exertion to receive it with purity and devotion.
Ceremonies Of Confirmation
It remains now briefly to glance at the rites and ceremonies used by the Catholic Church in the administration of this Sacrament; and pastors will understand the great advantages of this explanation, if they revert to what we already said on this subject under its proper head.
The Anointing Of The Forehead
The forehead, then, of the persons to be confirmed is anointed with sacred chrism; for by this Sacrament the Holy Spirit infuses Himself into the souls of the faithful, and increases in them strength and fortitude to enable them, in the spiritual contest, to fight manfully and to resist their most wicked foes. Wherefore it is indicated that they are to be deterred by no fear or shame, the signs of which appear chiefly on the forehead, from the open confession of the name of Christ.
The Sign Of The Cross
Besides, that mark by which the Christian is distinguished from all others, as the soldier is by certain badges, should be impressed on the more conspicuous part of the body.
Time When Confirmation Should Be Conferred
It has also been a matter of solemn religious observance in the Church of God that this Sacrament should be administered principally at Pentecost, because on that day especially were the Apostles strengthened and confirmed by the power of the Holy Ghost. By the recollection of this supernatural event the faithful should be admonished of the nature and magnitude of the mysteries contained in the sacred unction.
The Slap On The Cheek
The person when anointed and confirmed next receives a gentle slap on the cheek from the hand of the Bishop to make him recollect that, as a valiant combatant, he should be prepared to endure with unconquered spirit all adversities for the name of Christ.
The Pax
Lastly, the peace is given him, that he may understand that he has attained the fullness of divine grace and that peace which passeth all understanding.
Admonition
Let this, then, serve as a summary of those things which pastors are to expound touching the Sacrament of chrism. The exposition, however, should not be given so much in empty words and cold language, as in the burning accents of pious and glowing zeal, so as to seem to imprint them on the souls and inmost thoughts of the faithful.