224. What is the second commandment of God?
The second commandment of God is: Thou shalt not take the name of the Lord thy God in vain.

225. What are we commanded by the second commandment?
By the second commandment we are commanded always to speak with reverence of God, of the saints, and of holy things, and to be truthful in taking oaths and faithful to them and to our vows.

226. What is an oath?
An oath is the calling on God to witness the truth of what we say.

227. What things are necessary to make an oath lawful?
To make an oath lawful, three things are necessary: first, we must have a good reason for taking an oath; second, we must be convinced that what we say under oath is true; third, we must not swear, that is, take an oath, to do what is wrong.

228. What great sin does a person commit who deliberately calls on God to bear witness to a lie?
A person who deliberately calls on God to bear witness to a lie commits the very grievous sin of perjury.

229. What is a vow?
A vow is a deliberate promise made to God by which a person binds himself under pain of sin to do something that is especially pleasing to God.

230. What is meant by taking God's name in vain?
By taking God's name in vain is meant that the name of God or the holy name of Jesus Christ is used without reverence; for example, to express surprise or anger.

231. Is it a sin to take God's name in vain?
It is a sin to take God's name in vain; ordinarily, it is a venial sin.

232. What is cursing?
Cursing is the calling down of some evil on a person, place, or thing.

233. What is blasphemy?
Blasphemy is insulting language which expresses contempt for God, either directly or through His saints and holy things.

234. What is the third commandment of God?

The third commandment of God is: Remember thou keep holy the Lord's day.

235. Why does the Church command us to keep Sunday as the Lord's day?
The Church commands us to keep Sunday as the Lord's day, because on Sunday Christ rose from the dead, and on Sunday the Holy Ghost descended upon the apostles.

236. What are we commanded by the third commandment?
By the third commandment we are commanded to worship God in a special manner on Sunday, the Lord's day.

237. How does the Church command us to worship God on Sunday?
The Church commands us to worship God on Sunday by assisting at the Holy Sacrifice of the Mass.

238. What is forbidden by the third commandment of God?
By the third commandment of God all unnecessary servile work on Sunday is forbidden.

239. What is servile work?
Servile work is that which requires labor of body rather than of mind.

240. When is servile work allowed on Sunday?
Servile work is allowed on Sunday when the honor of God, our own need, or that of our neighbor requires it.