At the end of three years thou shalt {h} bring forth all the tithe of thine increase the same year, and shalt lay it up within thy gates:

(h) Besides the yearly tithes that were given to the Levites, these were laid up in store for the poor.

Wesley's Notes

14:28 At the end of three years - That is, in the third year, as it is, expressed, Deu 26:12. The same year - This is added to shew that he speaks of the third year, and not of the fourth year, as some might conjecture from the phrase, at the end of three years.

Jamieson-Fausset-Brown Bible Commentary

28, 29. At the end of three years . the Levite . shall come, &c.-The Levites having no inheritance like the other tribes, the Israelites were not to forget them, but honestly to tithe their increase [Nu 18:24]. Besides the tenth of all the land produce, they had forty-eight cities, with the surrounding grounds [Nu 35:7], "the best of the land," and a certain proportion of the sacrifices as their allotted perquisites. They had, therefore, if not an affluent, yet a comfortable and independent, fund for their support.

Matthew Henry's Concise Commentary

14:22-29 A second portion from the produce of their land was required. The whole appointment evidently was against the covetousness, distrust, and selfishness of the human heart. It promoted friendliness, liberality, and cheerfulness, and raised a fund for the relief of the poor. They were taught that their worldly portion was most comfortably enjoyed, when shared with their brethren who were in want. If we thus serve God, and do good with what we have, it is promised that the Lord our God will bless us in all the works of our land. The blessing of God is all to our outward prosperity; and without that blessing, the work of our hands will bring nothing to pass. The blessing descends upon the working hand. Expect not that God should bless thee in thy idleness and love of ease. And it descends upon the giving hand. He who thus scatters, certainly increases; and to be free and generous in the support of religion, and any good work, is the surest and safest way of thriving.