(5 ILCS 255/4) (from Ch. 101, par. 4)

Sec. 4. Whenever any person required to take or subscribe an oath, as aforesaid, and in all cases where an oath is upon any lawful occasion to be administered, and such person shall have conscientious scruples against taking an oath, he shall be admitted, instead of taking an oath, to make his solemn affirmation or declaration in the following form to-wit: You do solemnly, sincerely and truly declare and affirm. Which solemn affirmation or declaration shall be equally valid as if such person had taken an oath in the usual form; and every person guilty of falsely and corruptly declaring, as aforesaid, shall incur and suffer the like pains and penalties as are or shall be inflicted on persons convicted of willful and corrupt perjury.

(Source: R.S. 1874, p. 725.)