then you will delight yourself in Yahweh,
and I will cause you to ride on the high places of the land,
and I will feed you with the inheritance of Jacob your father;”
for the mouth of Yahweh has spoken it. Bible other translations

“feed you with the inheritance of Jacob.” “The inheritance of Jacob” is the land of Israel, which was promised to Abraham, Isaac, Jacob, and Israel. In this verse, “the inheritance of Jacob” is put by metonymy for the abundance of food produced in the land of Israel—God would feed Israel with an abundance of food produced in the land. Many verses in the Old Testament foretell a time when the land and waters will be healed and the deserts will bloom, so food and wine will be abundant for both man and animals (Isa. 25:6; 30:23-26; 32:15; 35:1-7; 41:18-20; 44:3; 51:3; Jer. 31:5, 11-14; Ezek. 47:1, 2, 7-12; Hos. 2:21-22; Joel 2:18-26; 3:18; Amos 9:13). The abundance of the food in the Messianic Kingdom is linked to the feast that God will throw for the people of the Kingdom. [For more on the promise of the land to Abraham, Isaac, and Jacob as an inheritance, see commentary on Genesis 15:18. For more on the great feast in the Kingdom of Heaven, the Messianic Kingdom on earth, see commentary on Matthew 8:12].

For the one talking at the end of the verse not being the Messiah, see Barnes notes (and Calvin’s commentary?)

Commentary for: Isaiah 58:14