With respect to the number of the sacraments, which was reduced by Luther and Calvin to two sacraments, all seven sacraments are instituted by Christ. And this is de fide, I. e, a matter of Catholic faith, which means no historical doubt as to whether they are really instituted by Christ or not is allowed any more If you read in a Catholic book the formulation of a dogma and then under this formulation the two words “de fide,” then this means it is a matter of dogmatic statement of the Roman church which you cannot deny or doubt, except by risk of being cut off from the Roman church.