The great mystery of the union in Christ of a human nature with the second Person of the Godhead is that the human actions and sufferings of Christ are divine actions and sufferings. The sacraments are a living continuation of this mystery. There are earthly, external signs here which, of themselves, could never acquire any supernatural significance, but the signs of the sacraments have been made by Christ into vehicles of his grace. They effect in men the grace for which Christ made them the sign.
So there are two fundamental ideas which constantly recur in the Church's teaching on the sacraments. First there is the Church's concern for these instituted by Christ, their number, and their proper preservation and administration; then the grace which Christ has for all time linked with these signs and which is communicated by them.
The second is the effect of the sacraments. They are the signs of Christ's work; the effectiveness of Christ's continuing work in his Church cannot be dependent on man's inadequacy. A sacrament, administered properly in the way established by Christ and with the proper intention, gives the grace it signifies. It is effective not by reason of the power of intercession of priestly prayer nor on account of the worthiness of the recipient, but solely by the power of Christ. The power of Christ lives in the sacraments. The effect of the sacrament is independent of the sinfulness or unworthiness of the minister. The Church has never tolerated any subjective qualification of the objective effectiveness of the sacraments ex opere operato. This would ultimately be to conceive the way of salvation as being man's way to God and not God's way to man.
The Church Thus Teaches: There are seven sacraments. They were instituted by Christ and given to the Church to administer. They are necessary for salvation. The sacraments are the vehicles of grace which they convey. They are validly administered by the carrying out of the sign with the proper intention. Not all are equally qualified to administer all the sacraments. The validity of the sacrament is independent of the worthiness of the minister. Three sacraments imprint an indelible character.
Sacramentals are instituted by the Church and are effective by virtue of the Church's intercession. Institution and alteration of them is reserved to the Holy See.