The story
From the Bible account of the poor widow’s donation of two mites (or leptons, small coins of low value) to the temple contribution box, which Jesus Christ praised as more than the gifts presented by wealthy people, for “[a]ll these people gave their gifts out of their wealth; but she out of her poverty put in all she had to live on”: Luke 21:1–4 (New International Version); see also Mark 12:38–44.
Etymology from Wiktionary, CC BY-SA 4.0.