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.
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.