Matthew 6:1
Beware of practicing your piety before men in order to be seen by them; for then you will have no reward from your Father who is in heaven.
"Piety" is one of those words, like "righteousness," that has fallen on hard times. For most people it's a word that has largely negative connotations. Just as calling someone a "righteous" person is basically a way of calling them a self-righteous person, so calling someone a "pious" person is typically a way of saying he or she is a gooey, religious, ostentatiously devout Church Lady. That's too bad, because piety has a positive meaning that we are impoverished to lose. "Piety" means a sense of duty to God which is not looking for applause or earthly reward. Usually, pious duties are carried out in mundane ways (the Sermon on the Mount focuses on the quiet and unobtrusive disciplines of prayer, almsgiving and fasting). Most people at most times who seek to be pious are doing such unseen and unsung things and having a colossal and largely hidden influence for good on the world thereby. But to get the hang of what piety means we are sometimes confronted with such unseen and unsung sacrifices writ large across the page of history. So, for instance, it was an act of piety for the people on United Flight 93 to fight their attackers on September 11, 2001 in the full knowledge that by their sacrifice, they would certainly die, yet save untold thousands of other people. They received nothing from men, but we may well believe that their reward from the Father in heaven was very great. Blessed indeed are the pious.