According to Isaiah 43:11, God alone is our Savior. We don’t need or recognize any other saviors
Isaiah 43:11 is written with reference to other “gods,” and it teaches emphatically that the Jewish people will not be saved by any other so-called god or deliverer. This is clear. It is also clear that God saves through whom he wills to save—whether it be earthly deliverers (such as kings or warriors), angelic messengers, or the Messiah.
The answer to this objection is self-evident if we consult a Hebrew concordance, since the word moshiʾa (savior) occurs more than thirty times in the Bible, almost every time with reference to someone other than Yahweh. So, for example, it is written in Judges 3:9 that when the Israelites cried out to the Lord, he raised up a savior (or deliverer) for them (cf. also Judg. 3:15; 12:3), and in Isaiah 19:20, God promises that he will one day send Egypt a savior and defender who will rescue them—again with reference to someone other than the Lord.
In a similar way, Isaiah 33:22 says that God is our lawgiver, judge, and king, but we know, of course, that he used Moses to give us the law, that he raised up numerous judges for Israel, and that the Messiah is known as King Messiah. There is no contradiction here at all.
The simple point is this: God, the only Savior, uses whom he will to deliver his people, and both traditional Judaism and the New Testament recognized that the Messiah would be the Lord’s appointed Savior par excellence. Thus, the prayer for the Davidic Messiah in the Amidah (also called the Shemoneh Esreh, i.e., the eighteen foundational petitions in Judaism) talks about waiting for God’s salvation to come through his Messiah, the one literally called “the horn of salvation.” In fact, the footnote to this benediction in the ArtScroll Siddur (reflecting traditional Jewish scholarship) reads, “Here we are taught that the ultimate salvation of the Jewish people is possible only through the Davidic Messiah.”88 Well said!
88 Scherman, ArtScroll Siddur, 108, “Davidic Reign.” It is also ironic that anti-missionaries object to the idea of the Messiah being divine (see above, 3.2–3.3) and then turn around and object to a non-divine Messiah being the savior since God alone is the Savior! On the necessity of the Messiah being divine in order to pay for the sins of the world, see Wayne Grudem, Systematic Theology (Grand Rapids: Zondervan, 1994), 578.
Brown, M. L. (2000). Answering Jewish objections to Jesus, Volume 2: Theological objections (59). Grand Rapids, Mich.: Baker Books.