SB 11.18.19
bahir jalasayam gatva
tatropasprsya vag-yatah
vibhajya pavitam sesam
bhuñjitasesam ahrtam
Translation:
Taking the food gathered through begging, one should leave the populated areas and go to a reservoir of water in a secluded place. There, having taken a bath and washed one’s hands thoroughly, one should distribute portions of the food to others who may request it. One should do this without speaking. Then, having thoroughly cleansed the remnants, one should eat everything on one’s plate, leaving nothing for future consumption.
Purport:
Srila Bhaktisiddhanta Sarasvati Thakura explains that a saintly person should not argue or quarrel with materialistic persons who may request or demand part of his foodstuff. The word vibhajya indicates that one should give something to such persons to avoid disturbance, and then, offering the remnants to Lord Visnu, one should eat everything on one’s plate, without saving food for the future. The word bahih indicates that one should not eat in a public place, and vag-yata indicates that one should eat silently, meditating upon the Lord’s mercy.