faithfulness

noun

Faithfulness or devotion to a person, a cause, obligations, or duties: allegiance, constancy, fealty, fidelity, loyalty, steadfastness. See continue/stop/pause, obligation.

The noun has one meaning:

Meaning #1: the quality of being faithful
  Synonym: fidelity
  Antonym: unfaithfulness (meaning #1)

Quotes:

"We must do our business faithfully, without trouble or disquiet, recalling our mind to God mildly, and with tranquility, as often as we find it wandering from him." - Brother Lawrence

"Some people say Liz and I are whores, but we are saints. We do not hide our loves hypocritically, and when in love, we are loyal and faithful to our men. [On the subject of her multiple marriages]" - Ava Gardner

"Faithfulness and sincerity are the highest things." - Confucius

"It is better to be unfaithful than faithful without wanting to be." - Brigitte Bardot

"By faithfulness we are collected and wound up into unity within ourselves, whereas we had been scattered abroad in multiplicity." - St. Augustine