**Why, does there need to be a Son, God the Father alone is God, and He does the saving.**
Because, FRiend, God is a Spirit, yet he made a physical world (through his Son) that he needed to redeem physically. The Son was only able to do this (as the scriptures prove) through the power of God the Father in him.
Jesus Christ is the Son of God. Peter got a big atta boy for that admission.
I, even I, am the LORD; and beside me there is no saviour.
You say, No,that's not correct, there is a saviour 'beside God', however that saviour is not God, but empowered by God?