en_tn/deu/14/28.md

every three years you will present all the tithe of your produce

Once every 3 years the Jews were to give their tithe to the town so that it would be used to provide for the Levites, orphans, widows and foreigners.

fatherless

children whose parents have both died and do not have relatives to care for them

widow

a woman whose husband has died and has no children to care for her in her old age