The Sacrament of Baptism
"Holy Baptism is the basis of the whole Christian life, the gateway to life in the Spirit, and the door which gives access to the other sacraments. Through Baptism we are freed from sin and reborn as sons (and daughters) of God; we become members of Christ, are incorporated into the Church and made sharers in her mission…"—Catechism of the Catholic Church (CCC 1213)
The Sacrament of Confirmation
“And while staying with them Jesus charged them not to depart from Jerusalem, but to wait for the promise of the Father, which, He said, ‘You heard from me, for John baptized with water, but before many days you shall be baptized with the Holy Spirit'”—(Acts 1:4-5).
Even though the apostles had lived with Jesus for three years, been witnesses of His miracles, and saw Him risen from the dead, it was not until they received the outpouring of the Holy Spirit on the Day of Pentecost that they were filled with courage to proclaim the Gospel to those around them. The Sacrament of Confirmation is the reception of that same Spirit, completing our initiation sending us out into the community to tell others of the Risen Lord.
The Sacrament of the Holy Eurcharist
Material food first changes into the one who eats it, and then, as a consequence, restores to him lost strength and increases his vitality. Spiritual food, on the other hand, changes the person who eats it into itself. Thus the effect proper to this Sacrament is the conversion of a man into Christ, so that he may no longer live, but Christ lives in him; consequently, it has the double effect of restoring the spiritual strength he had lost by his sins and defects, and of increasing the strength of his virtues.” St. Thomas, Commentary on Book IV of the Sentences, d.12, q.2, a.11