The Sacraments (in general)

A sacred sensible sign instituted by Christ in perpetuity to signify sanctifying grace and to confer that grace on the soul of the recipient. A sacrament is not fulfilled by the fact that one believes in it but by the fact that it is made. As sacraments cause grace it is obvious that they must depend on God for their institution, for grace is the gift of God alone. It is Catholic teaching that every one of the seven sacraments of the New Law was instituted by Christ. A sacrament consists essentially of three things; the matter, the form, and the minister who makes the sacrament with the intention of doing what the Church does; if any of these things be wanting, the sacrament is not made (confected).

(Definition from A Catholic Dictionary, 1951)
 

References in Scripture:

• See the pages for each individual Sacrament for specific verses on each. 

Church Teaching on the Sacraments (in general):

• "CANON I.- If any one saith, that the sacraments of the New Law were not all instituted by Jesus Christ, our Lord; or, that they are more, or less, than seven, to wit, Baptism, Confirmation, the Eucharist, Penance, Extreme Unction, Order, and Matrimony; or even that any one of these seven is not truly and properly a sacrament; let him be anathema." Council of Trent, On the Sacraments in General
• "CANON VI.- If any one saith, that the sacraments of the New Law do not contain the grace which they signify; or, that they do not confer that grace on those who do not place an obstacle thereunto; as though they were merely outward signs of grace or justice received through faith, and certain marks of the Christian profession, whereby believers are distinguished amongst men from unbelievers; let him be anathema." Council of Trent, On the Sacraments in General
• "These five sacraments -- Confirmation, Eucharist, Extreme Unction, Holy Orders and Matrimony -- are on that account called sacraments of the living, because those who receive them must be free from mortal sin, that is, already alive through sanctifying grace. Q: What sin does he commit who, conscious that he is not in a state of grace, receives one of the sacraments of the living?
  A: He who conscious that he is not in a state of grace, receives one of the sacraments of the living, commits a serious sacrilege" Catechism of St. Pius X, The Sacraments
• "However, let not the faithful imagine that it is enough to receive the body of the Lord once a year only, in obedience to the decree of the Church. They should approach oftener; but whether monthly, weekly, or daily, cannot be decided by any fixed universal rule. St. Augustine, however, lays down a most certain norm: Live in such a manner as to be able to receive every day" Catechism of Council of Trent, The Sacrament of the Eucharist (Sacraments of Confirmation, Holy Orders and Matrimony are received only one time in a person's life, and Extreme Unction only when in danger of death. The Sacrament of Penance is the only other Sacrament beside the Eucharist which is received regularly).

Church Teaching on Changing of any Sacraments:

• "It is well-known that to the Church there belongs no right whatsoever to innovate anything on the substance of the Sacraments" Pope St. Pius X, Ex quo nono, 1910
• "The Church is forbidden to change, or even touch, the matter or form of any Sacrament. She may indeed change or abolish or introduce something in the non-essential rites or "ceremonial" parts to be used in the administration of the Sacraments, such as the processions, prayers or hymns, before or after the actual words of the form are recited..." Pope Leo XIII, Apostolicae Curae, 1896
   

Summary

Christ instituted seven Sacraments through which we receive graces. The Catholic Church teaches there are seven Sacraments and that these cannot be added to, removed from, or changed.

The Sacrament of Baptism is the minimum Sacrament required to be saved, and if one sins mortally after Baptism, the Sacrament of Penance is also required to be able to be saved. To say otherwise is NOT Catholic!