What is gleaning or gathering in the scriptures?

"She  went,  and  came,  and  gleaned  in  the  field  after the  reapers." Ruth 2:3

The  Israelites  were  commanded  by  their  law  to  be  merciful  to  the  poor. The  corners  of  the  fields  were  not  to  be  reaped. ''When you reap the harvest of your land, do not reap to the very edges of your field or gather the gleanings of your harvest. Do not go over your vineyard a second time or pick up the grapes that have fallen. Leave them for the poor and the foreigner. I am the LORD your God. Leviticus 19:9-10 and ''When you are harvesting in your field and you overlook a sheaf, do not go back to get it. Leave it for the foreigner, the fatherless and the widow, so that the LORD your God may bless you in all the work of your hands.'' Deuteronomy 24:19 

This  grain  in  the  corners, and these odd sheaves in the field, were for the poor. The  story  of  Ruth  is  a  most  beautiful  illustration  of  this  law.  Reference  is  supposed  to  be  made  to  this  custom in  ''The poor must go about naked, without any clothing. They harvest food for others while they themselves are starving. They press out olive oil without being allowed to taste it, and they tread in the winepress as they suffer from thirst.'' Job 24:11-12