isaiah 58:14 Then shalt thou delight thyself in the LORD; and I will cause thee to ride upon the high places of the earth, and feed thee with the heritage of Jacob thy father: for the mouth of the LORD hath spoken it. - Free Bible Online

      14. delight . . . in . . . Lord--God rewards in kind, as He punishes in kind. As we "delight" in keeping God's "Sabbath," so God will give us "delight" in Himself (Ge 15:1; Job 22:21-26; Ps 37:4).
      ride upon . . . high places--I will make thee supreme lord of the land; the phrase is taken from a conqueror riding in his chariot, and occupying the hills and fastnesses of a country [VITRINGA], (De 32:13; Mic 1:3; Hab 3:19). Judea was a land of hills; the idea thus is, "I will restore thee to thine own land" [CALVIN]. The parallel words, "heritage of Jacob," confirm this (Ge 27:28, 29; 28:13-15).
      mouth of . . . Lord . . . spoken it--a formula to assure men of the fulfilment of any solemn promise which God has made (Isa 40:5).

JFB.