Catechism lesson 33: The Holy Name (LD 36, 37)

Because the LORD is holy, we must speak of him with reverence, and be careful not to give him a bad reputation.

LD 36 q&a 99.

What is required in the third commandment?

We are not to blaspheme or to abuse the name of God
by cursing, perjury, or unnecessary oaths,
nor to share in such horrible sins
by being silent bystanders.

Rather, we must use the holy name of God
only with fear and reverence,
so that we may rightly confess him,
call upon him,
and praise him in all our words and works.

LD 36 q&a 100.

Is the blaspheming of God’s name
by swearing and cursing
such a grievous sin
that God is angry also with those
who do not prevent and forbid it
as much as they can?

Certainly, for no sin is greater
or provokes God’s wrath more
than the blaspheming of his name.
That is why he commanded it to be punished
with death.

LD 37 q&a 101.

But may we swear an oath
by the name of God
in a godly manner?

Yes, when the government demands it
of its subjects,
or when necessity requires it,
in order to maintain and promote
fidelity and truth,
to God’s glory and for our neighbour’s good.

Such oath-taking is based on God’s Word
and was therefore rightly used
by saints in the Old and the New Testament.

LD 37 q&a 102.

May we also swear by saints
or other creatures?


A lawful oath is a calling upon God,
who alone knows the heart,
to bear witness to the truth,
and to punish me if I swear falsely.

No creature is worthy of such honour.


The third commandment forbids blasphemy: the abuse of God’s holy Name.

Often we think about “swearing” or “cussing”: using the names of holy things or crude words as expletives. It is better to avoid such expletives; crude language is disrespectful and reveals a lack of self-control. But blasphemy goes much deeper than using words in this off-handed manner.

You blaspheme God if you talk about him in a way that shows disrespect for who he is. For instance, if you pray to God to help you with something you know is wicked. If you claim to be serving him when you are deliberately sinning. If you say things about him that take away from his glory and truth.

Blasphemy does not drag down God, but it harms his reputation. If people see and hear us abuse the name of God, their opinion of him will be less. But the very purpose of our lives is to give glory and honour to God. Blasphemy is the exact opposite of what we should be saying and doing.

God takes blasphemy very seriously.

Read the story in Lev. 24:10-16. What did God tell Moses to do with a person who blasphemed?

God’s Old-Testament name is YHWH, “Yahweh”, usually translated as “the LORD”. It echoed God’s declaration: “I am who I am …” This name was precious to God’s people, because it expressed his unchanging love, his wonderful grace, and his faithfulness to his promises.

In the New Testament, we know the same God especially through Jesus Christ. “There is no other name given to people by which we must be saved.” (Acts 4:12) The name “Jesus” is therefore infinitely precious to us. It describes the Person who fulfilled God’s great love and saved us from our sins. If you realize that, you will treasure that name and use it will the greatest reverence!

Oaths and perjury

The Heidelberg Catechism has two Lord’s Days for the third commandment. There is a historical reason for this. In the mid-1500s, when the catechism was written, there were “radical” Reformers, known as Anabaptists, who thought that you should never use God’s name to swear an oath.

There are cases where an oath is important. If you are a witness against someone in court, and you lie in your testimony, then that person may be condemned unfairly. In extreme cases, he may even lose his life. Therefore the court may ask you to swear to God that you are speaking the truth. When you do this, you are saying: “May the greatest Judge of all, who knows all the truth, punish me if I am lying at this time.” In such an oath you are calling a curse upon yourself if you lie. This often happened in Bible times; it still happens today when people in sworn in in a court trial.

Read Mat 5:33-37. What conclusion did the Anabaptists draw from this text? What does the catechism say about this in q&a 101?

Sometimes it is necessary to mention that we are “honest to God”. In court we may be asked to do so publicly. In that case we do it. But Jesus’ point in Mat 5:37 is also true: it is best to always speak the plain truth, instead of feeling the need to use God’s name at the drop of a hat. A public oath in God’s name should be reserved for special circumstances.


  1. If a coworker says “Jesus” when something bad happens, is that blasphemy? Does it make a difference whether he knows the Lord or not? What is your response?
  2. Read 2 Kings 6:31. Explain why this is a clear violation of the third commandment.
  3. What are some ways in which you can promote God’s holy name? See q & a 99 for some ideas.


All: Memorize q&a 99.

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