Synopsis of the Books of the Bible, by John Nelson Darby, [1857-62], at sacred-texts.com
The following commentary covers Chapters 14 and 15.
Chapter 14 forbids that the people, as being the children of the living God, should imitate the profane customs which indicated the devotedness of idolaters to the impure beings they worshipped. God had chosen Israel for Himself. Neither were they to defile themselves by eating abominable things. They were a holy people. The tithes and all the firstfruits were to be offered to God.
Thus consecrated, each one might eat them in the place where God had put His name. The same command had been given (chap. 12) with regard to the place where they were to be eaten, with the addition that the children, menservants, and maidservants, might partake of them, applying it also to the vows, the free-will-offerings and the heave-offering. These ordinances are very remarkable. [See Note #1] Another, found at the end of chapter 14, may be added here. The tithe of the third year was to be laid up within their gates, and the Levite, the fatherless, and the stranger, were to come and eat of it; and he who did thus would be blessed of Jehovah in all the work of his hands. Here everything was sanctified, as having been presented to Jehovah. There was thus the recognition, on the one hand, that the people were His, on the other, that all they had was of Him; but in giving Him back what He had given them, they enjoyed, in fellowship with Him, and their families, the things common to God and the people, given by Him, offered to Him, and enjoyed in His presence in communion one with another, God Himself partaking of them, for the whole was offered to Him. It was not here the priests opening out a way for the people to draw near to God: God was honoured by the offering. God enjoyed the piety of the people, and the people themselves offered with joy. Seated before God Himself, in the joy of communion with Him, as at the same table, it was the people who enjoyed the privilege.
In the case of the tithe of the third year, it is not the family joy of the people with God, but rather the grace that brought enjoyment to those who were strangers or in want, and to the servants of God who had no inheritance. It was within their gates that this took place. They had the privilege of acting in grace from Jehovah, in communicating to His poor what He had given them. They did not go to the house of Jehovah, but they invited the widow, the orphan, and the Levite, to their house to rejoice, and Jehovah blessed them. The immediate relationship of the people with God in family fellowship and in grace here is very remarkable. The priests are out of the scene; the Levites being the objects of the liberality of the people, as having no inheritance (compare Deu 12:19).
Chapter 15 teaches each one among the people to consider with liberality and grace their poor brethren (this consideration being besides made sure to them by the year of release, which applied to debts and to the Hebrew slaves). The dependence of him, who thus respected Jehovah in His poor, was to be placed in God, who would bless him in thus acting according to His commandment; for the poor were His poor.
Note #1
It is generally explained that there was a double tithe; that is, that this does not refer to the regular tithe paid to the Levites, as ordered in the other places in the law, and that the Levitical tithes remained as they were according to the previous prescriptions of the law; and it is to be remarked they were to be locally paid to the Levites, not where Jehovah had placed His name. Two years they carried the different offerings to the place chosen of Jehovah, and ate and rejoiced, but the third, invited the Levite and the poor at home. gives us historically all these different tithes and offerings; only it appears that, the ten tribes being in rebellion and apostasy, pious people carried the Levitical tithes to Jerusalem. Amo 4:4 shews. there was some special habit of tithing every third year, then at Bethel. At any rate what characterises Deuteronomy is their enjoying God's goodness together, and making the poor enjoy it with them, Levites and strangers; while priests, though named, are on these points wholly ignored (see Deu 12:6-7; Deu 12:11-12; Deu 12:17-18; Deu 14:22-28). The priests' portion is in Deu 18:3-4. But firstlings and firstfruits in chapter 12 are not the same word; nor is Deu 14:23. But the whole tone of Deuteronomy is fellowship and enjoyment only before the Lord, not priestly or altar service.