The wording in these verses is so powerful. I pulled a few New Testament verse that say much the same. There is no lack of consistency in the Bible between old and new.
Isa 48:12 Hearken unto me, O Jacob and Israel, my called; I am he; I am the first, I also am the last. Rev 1:8 I am Alpha and Omega, the beginning and the ending, saith the Lord, which is, and which was, and which is to come, the Almighty. Rev 1:4 John to the seven churches which are in Asia: Grace be unto you, and peace, from him which is, and which was, and which is to come; and from the seven Spirits which are before his throne; Isa 48:13 Mine hand also hath laid the foundation of the earth, and my right hand hath spanned the heavens: when I call unto them, they stand up together. Isa 48:17 Thus saith the LORD, thy Redeemer, the Holy One of Israel; I am the LORD thy God which teacheth thee to profit, which leadeth thee by the way that thou shouldest go. 2Ti 3:16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: 2Ti 3:17 That the man of God may be perfect, throughly furnished unto all good works. Isa 48:18 O that thou hadst hearkened to my commandments! then had thy peace been as a river, and thy righteousness as the waves of the sea:
Isa 49:6 And he said, It is a light thing that thou shouldest be my servant to raise up the tribes of Jacob, and to restore the preserved of Israel: I will also give thee for a light to the Gentiles, that thou mayest be my salvation unto the end of the earth. Luk 2:30 For mine eyes have seen thy salvation, Luk 2:31 Which thou hast prepared before the face of all people; Luk 2:32 A light to lighten the Gentiles, and the glory of thy people Israel.