How can a citizenship solemnization be 'religious'?

Question

[Source:] CEREMONIAL PROCEDURES OF CITIZENSHIP JUDGES

17. (1) The ceremonial procedures to be followed by citizenship judges shall be appropriate to impress on new citizens the responsibilities and privileges of citizenship and, without limiting the generality of the foregoing, a citizenship judge shall, during a ceremony held for the presentation of certificates of citizenship, ...

(b) subject to subsection 22(1), administer the oath of citizenship with dignity and solemnity, allowing the greatest possible freedom in the religious solemnization or the solemn affirmation thereof;

I'm guessing that the Canada citizenship ceremony is laic; so which definition of religious fits?
I'd guess Definition 1.3, but I doubt so, because it seems cheeky and delusive to characterise a LAIC solemnization as religious ?

Footnote: I encountered this problem while reading this.

Answer 1

Traditionally speaking, an oath involves the oath-taker swearing by something sacred, most often a deity or sacred object. If they're lying, they're showing profound disrespect for whatever they swore by, inviting the wrath of their deity of choice. This means that an oath is traditionally a religious act according to the normal meaning of the term "religious;" the notion that an oath is just a promise with nothing to do with religion is more modern.

That's why there's the reference to religious solemnization: because the person taking the oath is swearing according to their religious faith (an affirmation is the same thing without the religious aspect; that's why you see "solemnly swear or affirm" popping up in the texts of legal oaths, to give an option that has no religious significance). If you ever wondered why Bibles are often used in oath-taking ceremonies, that's why.

Answer 2

To a pious Christian monarchist (who is not a member of a sect with religious objections to swearing oaths to the government), all three definitions of "religious" apply.

Fundamentally, an oath of citizenship is an oath of fealty. Canada's sovereign is styled "Her Majesty Elizabeth the Second, by the Grace of God of the United Kingdom, Canada and Her other Realms and Territories Queen, Head of the Commonwealth, Defender of the Faith". In theory, Canada's monarch still reigns by divine right.

Historically, the reason for the choice between "religious solemnization" and "solemn affirmation" is that some Christians believe that it is blasphemous to take a religious oath for a secular purpose. (Some denominations interpret such an oath to be a violation of the Third Commandment.) In English law, this choice goes back to 1695. The U.S. Constitution consistently offers a choice of "Oath or Affirmation".