Isaiah's monotheistic declarations that God alone is Savior and Rock are not contradicted by Jesus being called Rock and Savior — Jesus is God.

Winger answers simply: Jesus is God, so there is no contradiction. The Isaiah 40s section is an extended monotheistic argument — God alone laid the foundations of the earth, God alone is Savior. The New Testament affirms that all things were made through Christ (John 1:3, Colossians 1:16), which appears to conflict with Isaiah's "alone" — but is resolved by Trinitarian theology: the Father, Son, and Spirit are one God acting together at creation. "Alone" means without any other being, not without the other persons of the Trinity. The deity of Christ and the doctrine of the Trinity together resolve what would otherwise be a contradiction.