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.
At harvest the field was not to be reaped to its very corners and no second gathering of fallen grain was to be made, but the corners and the gleanings were to be left for the poor and the stranger instead of collecting everything. That reservation made provision for the needy an integral part of the harvest regulation rather than an afterthought. It rested on the ownership of the land and its yield as God's, with His people holding what they harvested as stewards entrusted with it.
The arrangement displayed care, kindness and welcome toward the destitute, and toward outsiders in particular, by bringing strangers into a share of the community's material provision. Welcoming them into the harvest also opened access to spiritual good, so that those who came to acknowledge God could share those blessings and be taught His law.
The portion left supplied food for the poor. It reflects the divine intent that those who have should assist those laboring to secure a footing, dealing with others in generosity and mercy. That same spirit requires that the work of others not be made unnecessarily difficult.