oblation vs widow's mite

oblation

noun
  • A deed or gift offered charitably. 

  • The offering of worship, thanks etc. to a deity. 

widow's mite

noun
  • A very small gift or donation which, however, represents a great sacrifice on the part of the giver. 

  • The lepton coin. 

How often have the words oblation and widow's mite occurred in a corpus of books? (source: Google Ngram Viewer )