Adam Clarke on Deuteronomy 26:11

Thou shalt rejoice - God intends that his followers shall be happy; that they shall eat their bread with gladness and singleness of heart, praising him. Those who eat their meat grudgingly, under the pretense of their unworthiness, etc., profane God's bounties and shall have no thanks for their voluntary humility.

Thou, and the Levite, and the stranger - They were to take care to share God's bounties among all those who were dependent on them. The Levite has no inheritance, let him rejoice with thee. The stranger has no home, let him feel thee to be his friend and his father.