Administer an Oath or Affirmation
One of the most important duties of the Notary is to administer oaths and affirmations, which are solemn promises of truthfulness or fidelity made by a signer, witness, or new office-holder. An oath is a pledge on one's personal honor, but both are legally equivalent and subject the oath-taker or affirmant to penalties for perjury. Both may be notarial acts in their own right -- as "swearing in" a new public official -- or they may be part of the process of performing an acknowledgment or jurat notarization.
It is customary for the Notary to ask the oath-taker or affirmant to raise a right hand in a pledging gesture or to place it over one's heart. The Notary has discretion to require any bit of ceremony -- such as placing one's left hand on a Bible or other revered text -- that the Notary believes will be most compelling by appeal to the individual's conscience. Oaths and affirmations should be taken seriously and always administered with a degree of formality.