Catholicism is an incarnational religion. What does that mean? It means that the Church recognizes the inherent goodness in Creation. We read in Genesis Chapter 1 that after God created the whole universe, He proclaimed it "good." Even after the Fall, when Creation was thrown in disarray and wounded by Man's disobedience, the Second Person of the Trinity came down from Heaven and entered Creation, becoming a man.
Therefore, Matter really matters. As Pope Benedict XVI wrote
. . .all of creation, in the end, is conceived of to create a place of encounter between God and His creature--a place where the history of love between God and His creature can develop.
This is the Sacramental Principle of Catholicism explained in one sentence! God uses the very things of this world to convey His love and His life to us. We see this clearly in Genesis, when God forms Man out of the clay of the earth and breathes into his nostrils the Breath of Life (Gen 2:7). Jesus also used the things of this world to convey His life, such as when he used spit to heal a deaf man (Mark 7:33-35), or mud to heal a blind man (John 9). We see this most powerfully during the Last Supper when Jesus took bread and wine and transformed them into His Body and Blood.
Sacraments, therefore, are encounters with the Living God, through outward signs and symbols, through which we receive the very life of God (grace). Continuing the Revelation found in Scripture and Tradition, the Church celebrates the Seven Sacraments which Jesus Himself instituted as the ordinary means by which we receive this Divine Life.
Baptism Matthew 28:18-20
Confirmation John 16:7-15, John 14:15-18; 26
Eucharist Mark 6:34-44, 1 Corinthians 11:23-26
Penance/Reconciliation John 20:19-23, Matthew 16:19
Anointing of the Sick Mark 6:13, Mark 16:18, James 5:13-15
Holy Orders John 13: 1-10, John 20:19-23, Luke 22:14-19
Matrimony John 2:1-11