What is the difference between "I swear" and "I affirm"

Question

In court oaths, there is the option to admit one of the following:

1. I [...] swear [...] so help me God.
2. I [...] affirm [...].

What is the significant difference? I am looking for code, statute, law, or perhaps a written reference to tradition.

Answer 1

In common law countries, the first law allowing affirmation in court was the Quaker Act 1695 . This was limited specifically to Quakers and didn't permit them to give evidence in criminal proceeedings or to serve on juries. The form of the affirmation given is:

I A.B. do declare in the Presence of Almighty God the Witnesse of the Truth of what I say.

Quakers, and various other Christian denominations use as biblical authority for this James 5:12, amongst other passages:

But above all things, my brethren, swear not, neither by heaven, neither by the earth, neither by any other oath: but let your yea be yea; and your nay, nay; lest ye fall into condemnation.

It wasn't until (often much) later the various common law countries held that an affirmation by an atheist was considered equivalent to swearing an oath.

A long discussion is available from the Irish Law Reform Commission.

Answer 2

An oath, which is what you make when you "swear" something, is formally speaking a promise made to God upon which you expect others to rely, and is one for of statement that can give rise to a perjury conviction.

An affirmation is a statement that you state is true under penalty of perjury made only to other men and women and not to God. It is preferred by those who are non-religious and by those who feel that oaths are an improper or sacrilegious act akin to taking the Lord's name in vain or idolatry.

Sometimes a written statement made with an affirmation is called a declaration, while a written statement made with an oath is called an affidavit, but the actual use of those words is not terribly precise.

Functionally, they are equivalent.

It is also worth noting that only certain officials (e.g. notaries, court reporters and judges) have the authority to put someone under oath, while not all affirmations require a specially authorized official to administer an oath (although many affirmations are made before such an official). If a document is called a "Declaration" it is generally affirmed rather than sworn, and is generally not notarized.

Answer 3

No difference as to the legal effect.

The two versions exist simply to fit religious and secular persons respectively.

I am looking for code, statute, law, or perhaps a written reference to tradition.

Depends on the jurisdiction, but will basically say the same everywhere where the two forms are used.