Christ is God, and also died for the sins of man.
Have you considered what a coward the Father must be, to create a finite human being and force him to go to the Cross to pay for the sins of mankind; and didn't do it Himself?
But this is not what happened. In Isaiah 9:6 it becomes clear that the son who was given was and is the everlasting Father. In order, also, to make that scripture not say what it clearly is teaching, one has to change the wording of the scripture twice.
Also, there is clearly one Lord in holy scripture (Ephesians 4:5, 1 Corinthians 8:6); and this Lord is the Father (Matthew 11:25, Luke 10:21). Yet, no one can say that Jesus is the Lord except by the Holy Ghost (1 Corinthians 12:3), even the Spirit of truth. And Jesus is the Lord (1 Corinthians 8:6).
This would indicate that Jesus, being the one Lord, is the same Person who was previously said to be the one Lord.
Only the Son is in human flesh and the Father is an eternal Spirit who inhabiteth eternity. And the Holy Ghost is also an eternal Spirit who inhabits eternity; and has behind Him an understanding of what it means to be human (see Luke 23:46); while the Father doesn't. Yet they are the same Spirit (Ephesians 4:4, 1 Corinthians 12:4-6); while the Holy Ghost proceedeth from the Father (John 15:26). This is because the eternal Spirit (the Father) took on human flesh;
Eph 3:11, According to the eternal purpose which he purposed in Christ Jesus our Lord:
And subsequently released His Spirit out of that flesh back to the eternal Spirit who inhabiteth eternity.
For because He inhabiteth eternity, He cannot cease to dwell in eternity, even though He descends.
Because the nature of someone inhabiting eternity is that they are there eternally.
Hope this helps.
The Trinity is really not that hard to understand once you know what it is all about.