Introduction

(Summa Theologica, II-II, q. 16.)

Unlike the commandments of justice, which are summed up in the Decalogue, the commandments of faith are not given in any one place of scripture; but they may be reduced to three: (a) one must acquire knowledge and understanding of one’s faith according to one’s state in life and duties; (b) one must believe internally the truths of faith; (c) one must profess externally one’s belief.