347. Q. What is an oath?
A. An oath is the calling upon God to witness the truth of what we say.

348. Q. When may we take an oath?
A. We may take an oath when it is ordered by lawful authority or
required for God's honor or for our own or our neighbor's good.

349. Q. What is necessary to make an oath lawful?
A. To make an oath lawful it is necessary that what we swear to, be
true, and that there be a sufficient cause for taking an oath.

350. Q. What is a vow?
A. A vow is a deliberate promise made to God to do something that is
pleasing to Him.

351. Q. Is it a sin not to fulfill our vows?
A. Not to fulfill our vows is a sin, mortal or venial, according to the
nature of the vow and the intention we had in making it.

352. Q. What is forbidden by the second Commandment?
A. The second Commandment forbids all false, rash, unjust, and
unnecessary oaths, blasphemy, cursing, and profane words.

353. Q. What is the third Commandment?
A. The third Commandment is: Remember thou keep holy the Sabbath day.

354. Q. What are we commanded by the third Commandment?
A. By the third Commandment we are commanded to keep holy the Lord's day
and the holydays of obligation, on which we are to give our time to the
service and worship of God.