If a doctrine is not de fide divina et catholica, a person is not an heretic for denying or doubting it, though such a denial or doubt may be grave sin.

A doctrine is de fide divina et catholica only when it has been infallibly declared by the Church to be revealed by God. Hence this term does not apply to doctrines which one knows to have been revealed by God, but which have not been declared by the Church to have been so revealed (de fide divina); nor to those which the Church has infallibly declared, but which she does not present formally as having been revealed (de fide ecclesiastica); nor to those which the Church teaches without exercising her infallible authority upon them.

8. Wherefore, by Divine and Catholic faith all those things are to be believed which are contained in the word of God as found in Scripture and tradition, and which are proposed by the Church as matters to be believed as divinely revealed, whether by her solemn judgment or in her Ordinary and Universal Magisterium.