A Sacrament is a visible form of invisible grace. Grace is God's gift to us for our salvation.
There are seven Sacraments: Baptism, Confirmation, the Eucharist, Penance, Anointing of the Sick, Holy Orders,and Matrimony. The first five of these Sacraments are intended to bring about the perfection of the individual man in himself; whereas the other two, Holy Orders and Matrimony, are so constituted that they perfect and multiply the entire Church.
THE SPIRITUAL AND THE PHYSICAL LIFE: AN ANALOGY
The spiritual life conforms to the physical life. In the physical life man is perfected in three chief ways: first, by generation, in that he is born into this world; secondly, by growth, through which he is brought up into stature and perfect strength; thirdly, by food which sustains man's life and powers. This would suffice were it not that man is attacked by illnesses, and hence, fourthly, he needs something which will bring him back to health.
This also holds true in the spiritual life. First, man needs regeneration or re-birth which is brought through the Sacrament of Baptism: "Unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God."(John 3:3) Secondly, it is necessary that man develop perfect strength, which is, as it were, a spiritual growth, and this indeed comes to him in the Sacrament of Confirmation. This is like the strengthening which the Apostles received when the Holy Ghost came upon them and confirmed them. The Lord had said to them: "But stay you in the city of Jerusalem till you be endued with power from on high."(Luke 24:49) The third similarity is that man must be fed with spiritual food through the Eucharist: "Unless you eat the flesh of the Son of Man, and drink His blood, you shall not have life in you."(John 6:53) Fourthly, man must be healed spiritually through the Sacrament of Penance: "Heal, O Lord, my soul, for I have sinned against Thee."(Psalm 41:4) Lastly, one is healed both in soul and in body in the Sacrament of Extreme Unction or Anointing of the Sick. "Is any man sick among you? Let him bring in the priests of the church, and let them pray over him, anointing him with oil in the name of the Lord. And the prayer of faith shall save the sick man, and the Lord shall raise him up, and if he be in sins, they shall be forgiven him."(James 5: 14-16)
Two of the Sacraments, Holy Orders and Matrimony, are instituted for the common good of the Church. Through the Sacrament of Holy Orders the Church is ruled and is spiritually multiplied; and through Matrimony it is increased physically in numbers. For Matrimony read Mark 10:3-9 and Matthew 19:6.
The effect of the Sacrament can be impeded through the fault of the recipient, for example, if one feigns to receive it and with a heart unprepared to receive worthily. Such a one, although he actually receives the Sacrament, does not receive the effect of the Sacrament, that is, the grace of the Holy Spirit. "For the Holy Spirit of discipline will flee from the deceitful." (Wisdom 1:5)