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5)  HOW DOES CHANGING THE FORM INVALIDATE A SACRAMENT?

Changes Caused by Omission of Words
38.  The omission of words in the form of a sacrament does not always invalidate the sacrament.  But the sacrament remains valid if and only if the words left out do not belong to the substance of the form; that is, the essence or necessary part of the form.  Thus we saw in paragraph 20 above that the omission of the word for in the form: For this is My Body, does not invalidate the sacrament, because the word for is not in the substance of the form.

39.  But it goes without saying that if the substance of the form is altered by the omission, then the sacrament is invalidated.  As St. Thomas says: "Now it is clear, if any substantial part of the sacramental form be suppressed, that the essential sense of the words is destroyed; and consequently the sacrament is invalid."  (Summa Th., III, Q. 60, Art. 8).

Changes Caused by Addition of Words
40.  If words are added to the form of a sacrament, and these words introduce a change in the basic meaning (essential sense) of the form, then the sacrament is necessarily invalid.  Thus the form for baptism used by the Arians was: "I baptize thee in the name of the Father Who is greater, and of the Son Who is less."

41.  Another example of the addition of words which would render a sacrament invalid would be: "I baptize thee in the Name of the Father. . . etc., and of the Blessed Virgin Mary."  That is, if by saying this one intended to place the Mother of God on a par with the Blessed Trinity.

42.  If the words added involve no change of sense, then the sacrament remains valid.  Thus the Greeks use the form: The servant of God, N . . . is baptized in the name of the Father, etc.

Changes Caused by Substitution of Words
43.  The type of change which we are concerned with in the present discussion is one of substitution.  For the newly-introduced form has substituted, for you and for all men so that sins may be forgiven, for the words: for you and for many unto the forgiveness of sins.  Now a substitution always necessarily involves an omission and an addition; for the standing phrase is omitted and the new phrase is added.

44.  A substitution is permissible if the part inserted is exactly equivalent to the part taken out.  The form we use for the Sacrament of Confirmation contains: I confirm thee with the chrism of salvation.  But some say: I confirm thee with the chrism of sanctification.  St. Thomas explains, "Holiness is the cause of salvation.  Therefore it comes to the same whether we say chrism of salvation or of sanctification." (Summa Th., III, Q. 72, Art. 4).  However, to substitute the word faith instead of salvation, for example, would most probably render the sacrament invalid.