Leviticus 23:22
"And when ye reap the harvest of your land, thou shalt not make clean riddance of the corners of thy field when thou reapest, neither shalt thou gather any gleaning of thy harvest: thou shalt leave them unto the poor, and to the stranger: I am the LORD your God."
Cross References (ranked by relevance)
Isaiah 58:10
And if thou draw out thy soul to the hungry, and satisfy the afflicted soul; then shall thy light rise in obscurity, and thy darkness be as the noon day:
Luke 11:41
But rather give alms of such things as ye have; and, behold, all things are clean unto you.
Psalm 112:9
He hath dispersed, he hath given to the poor; his righteousness endureth for ever; his horn shall be exalted with honour.