Q. 1164. {321} How does a person sin against faith?  A. A person sins against faith:  1st, By not trying to know what God has taught; 2d, by refusing to believe all that God has taught; 3d, by neglecting to profess his belief in what God has taught.

Q. 1165. {322} How do we fail to try to know what God has taught?  A. We fail to try to know what God has taught by neglecting to learn the Christian doctrine.

Q. 1166.  What means have we of learning the Christian doctrine?  A. We have many means of learning the Christian doctrine:  In youth we have Catechism and special instructions suited to our age; later we have sermons, missions, retreats, religious sodalities and societies through which we may learn.  At all times, we have books of instruction, and, above all, the priests of the Church, ever ready to teach us.  God will not excuse our ignorance if we neglect to learn our religion when He has given us the means.

Q. 1167.  Should we learn the Christian doctrine merely for our own sake?  A. We should learn the Christian doctrine not merely for our own sake, but for the sake also of others who may sincerely wish to learn from us the truths of our holy faith.

Q. 1168.  How should such instruction be given to those who ask it of us?  A. Such instruction should be given to those who ask it of us in a kind and Christian spirit, without dispute or bitterness.  We should never attempt to explain the truths of our religion unless we are certain of what we say.  When we are unable to answer what is asked we should send those who inquire to the priest or to others better instructed than ourselves.

Q. 1169. {323} Who are they who do not believe all that God has taught?  A. They who do not believe all that God has taught are the heretics and infidels.

Q. 1170.  Name the different classes of unbelievers and tell what they are.  A. The different classes of unbelievers are (1) Atheists, who deny there is a God; (2) Deists, who admit there is a God, but deny that He revealed a religion; (3) Agnostics, who will neither admit nor deny the existence of God; (4) Infidels, who have never been baptized, and who, through want of faith, refuse to be baptized; (5) Heretics, who have been baptized Christians, but do not believe all the articles of faith; (6) Schismatics, who have been baptized and believe all the articles of faith, but do not submit to the authority of the Pope; (7) Apostates, who have rejected the true religion, in which they formerly believed, to join a false religion; (8) Rationalists and Materialists, who believe only in material things.

Q. 1171.  Will the denial of only one article of faith make a person a heretic?  A. The denial of only one article of faith will make a person a heretic and guilty of mortal sin, because the Holy Scripture says:  “Whosoever shall keep the whole law but offend in one point is become guilty of all.”

Q. 1172.  What is an article of faith?  A. An article of faith is a revealed truth so important and so certain that no one can deny or doubt it without rejecting the testimony of God.  The Church very clearly points out what truths are articles of faith that we may distinguish them from pious beliefs and traditions, so that no one can be guilty of the sin of heresy without knowing it.