Targum Pseudo-Jonathan on (Genesis 14:20) preserves Shem-Malkizedek's blessing and the patriarch's response. Blessed be Eloha Ilaha, who hath made thine enemies as a shield which receiveth a blow. And he gave to him one of ten, of all which he brought back.
The image is military and strange. God has turned Abram's enemies into a shield that receives the blow. The Aramaic means that the four kings did not merely fail; they became the material that absorbed the strike intended for the righteous. The Most High used the wicked to cushion His ally. This is a deep theology of warfare. The enemy is not erased; the enemy is repositioned into the shield that deflects harm.
And then the tithe. He gave to him one of ten. Abram gives Shem-Malkizedek a tenth of the spoils — the first tithe in the Hebrew Bible, centuries before the laws of the Levitical tithe (Leviticus 27:30) will formalize the practice. The patriarch recognizes the priesthood of the Flood survivor by handing over a tenth of everything he has just rescued.
The Targumist is telling you that tithing is not a later ritual innovation. It is a patriarchal instinct. Abram, meeting a priest, does not bargain. He does not calculate. He gives one in ten.
Notice what is being exchanged. Shem-Malkizedek gives bread, wine, and a blessing. Abram gives a tenth of his spoils. This is the primal exchange of Jewish ritual life — the priest offers sacred provision, the people offer material return, and the Most High is named in the middle of both. A covenant of bread, blessing, and ten percent, struck on a Jerusalem hillside, long before the Temple that will later sit on that hill.