isaiah 63:8 For he said, Surely they are my people, children that will not lie: so he was their Saviour. - Free Bible Online

      8. he--Jehovah "said," that is, thought, in choosing them as His covenant-people; so "said" (Ps 95:10). Not that God was ignorant that the Jews would not keep faith with Him; but God is here said, according to human modes of thought to say within Himself what He might naturally have expected, as the result of His goodness to the Jews; thus the enormity of their unnatural perversity is the more vividly set forth.
      lie--prove false to Me (compare Ps 44:17).
      so--in virtue of His having chosen them, He became their Saviour. So the "therefore" (Jer 31:33). His eternal choice is the ground of His actually saving men (Eph 1:3, 4).

JFB.