Mark 12:42 Commentary - Whedon's Commentary on the Old and New Testaments

42. A certain poor widow Our Lord had just been launching reproofs against the proud who devoured widows’ houses. As if from the dim distance one of these widows seems to have appeared, whose house, perhaps, had been devoured, and in whose behalf our Lord had denounced the judgments of God.

She threw in two mites A mite was the smallest of Jewish coins; it was the fifth part of a cent. Less than a mite the widow could not contribute. To give a mite was a fair donation, but she will be munificent to God’s house and double the sum! The rabbins, however, seem to have had a rule forbidding the contribution of less than two mites.