In Genesis 28:22 Jacob makes a vow including a promise to give God a tenth (tithe) of whatever God gives to Jacob. Earlier we see Abraham give his tenth to the high priest of Salem, Melchizedek. And later, of course, a tithe is given to the Levites. But how was Jacob to give a tithe to God since there were no priests yet in his day?
It seems likely that Jacob would have given the tithe to God as a burnt offering. In the modern world, we are accustomed to thinking of tithes in terms of currency, but in the ancient Near East, the tithe came from the produce of the land:
You shall tithe all the yield of your seed that comes from the field year by year. And before the LORD your God, in the place that he will choose, to make his name dwell there, you shall eat the tithe of your grain, of your wine, and of your oil, and the firstborn of your herd and flock, that you may learn to fear the LORD your God always.
Specifically, in Jacob's case, his wealth is in the form of flocks. We see in Genesis 30-31, that God conspires against Laban to increase the wealth of Jacob by making Jacob's flocks grow. And it is from these flocks that he would have tithed. The customary way of doing so was through making an offering. We've seen already in Genesis the example of Abel in this regard:
Now Abel kept flocks, and Cain worked the soil. In the course of time Cain brought some of the fruits of the soil as an offering to the Lord. And Abel also brought an offering—fat portions from some of the firstborn of his flock.
While Abram did give the tithe to Melchizedek, Abel and the Patriarchs in Genesis are shown having unmediated access to bring offerings before God (cf. Gen. 35:14). Given that in making his vow Jacob builds an altar, this is likely the means by which he intends to give a tenth to God.
Before we can determine just how Jacob would pay his tithes, we have to examine the entire context of the passage.(Gen. 28:17-22)
And he was afraid, and said, How dreadful is this place! this is none other but the house of God, and this is the gate of heaven. 18 And Jacob rose up early in the morning, and took the stone that he had put for his pillows, and set it up for a pillar, and poured oil upon the top of it. 19 And he called the name of that place Bethel: but the name of that city was called Luz at the first. 20 And Jacob vowed a vow, saying, If God will be with me, and will keep me in this way that I go, and will give me bread to eat, and raiment to put on, 21 So that I come again to my father's house in peace; then shall the LORD be my God: 22 And this stone, which I have set for a pillar, shall be God's house: and of all that thou shalt give me I will surely give the tenth unto thee
Jacob sets his head down in a particular place, upon a rock, and he discovers that God is in this place and angels are ascending and descending. He then declares,"
And he was afraid, and said, How dreadful is this place! this is none other but the house of God, and this is the gate of heaven(Gen. 28:17)
So the context is the House of God, which would become the physical Temple. It is to the Temple that the tithes are paid; and where the storehouse is kept.(Mal. 3:10)
Bring ye all the tithes into the storehouse, that there may be meat in mine house, and prove me now herewith, saith the LORD of hosts, if I will not open you the windows of heaven, and pour you out a blessing, that there shall not be room enough to receive it.
Jacob's vow must be understood as more than an obligation: it is the promise of blessing that a Covenant God made with Abraham, confirmed through Isaac, and now he was the next in line to whom "All the families of the earth will be blessed".(Gen. 12:3)
The tithe is to be understood as part of our worship (Gen. 14:20),
And blessed be the most high God, which hath delivered thine enemies into thy hand. And he gave him tithes of all
Following Jacob's vow, he departed for Syria, where Laban, the brother of Rebecca his mother was. And after he came back, he was reminded by God of his vow(Gen 35:1), and he built an altar (Gen.35:3) :
And Jacob set up a pillar in the place where he talked with him, even a pillar of stone: and he poured a drink offering thereon, and he poured oil thereon. 15 And Jacob called the name of the place where God spake with him, Bethel
The tithe is the physical action in our worship to God, in honor of His Blessing and Provision in our lives. It doesn't exist as a separate act, but it is part of our response to God. That is why the tithes were to be "brought to the storehouse"(Mal. 3:10), it is the place in the Temple where the tithes were kept and to be distributed.
Jacob's act of building an altar, and later, pouring out offerings and making sacrifices on that altar, are a precursor to the "tithes" he would pay through his children, and later, his children by faith-who "rest" upon the Rock that Jacob had lain his head.
Jacob did not offer tithes. He offered alms. The tithes were offered in the covenant of Abraham (Gen 14:20). Remember that God made a covenant with Abraham and his son Isaac. Abraham's covenant was of circumcision-(Gen 17:7-13) The next covenant was made between God and Isaac. The everlasting covenant. (Gen 17:19) We are under the everlasting Covenant. We offer alms. Acts 10:4 And when he looked on him, he was afraid, and said, What is it, Lord? And he said unto him, thy prayers and thine alms are come up for a memorial before God. Alms- Food, Clothing, and Shelter, and let money be a last result because you are trying to get them dependent on money.
There is no record of Jacob fulfilling his vow to give God a tithe. So any answer as to how (or if) the vow was fulfilled involves conjecture.
At the time Jacob made his vow he had neither children nor flocks. When he returned to the place where he made his vow he had eleven sons, one daughter, and many animals. When Jacob returned to Bethel he only made a drink offering:
And Jacob set up a pillar in the place where he had spoken with him, a pillar of stone. He poured out a drink offering on it and poured oil on it. (Genesis 35:14 ESV)
One could conclude Jacob never gave the tithe he promised.
However, his youngest son at that time was Joseph. Later God would use Joseph for good:
As for you, you meant evil against me, but God meant it for good, to bring it about that many people should be kept alive, as they are today. (Genesis 50:20 ESV)
Joseph was taken for service to God. While not quite a “tithe” (Joseph was 1 of 12 children at the time Jacob returned), if Levi, the future priestly line, and Dinah (the only daughter) were excluded, Joseph would be one of the remaining 10 sons. In this sense God fulfilled Jacob's promise to tithe by taking Joseph away from Jacob for His purposes in Egypt.
Tithe is not limited to giving to the Levites and not only priests received tithe. Deuteronomy 14: 28 - 29 talks about the 'poor tithe'. It is more likely that Jacob started giving to the poor than looking for Melchizedek. After the destruction of the Temple, tithe went to the poor as it must have been in the time before the priesthood.