Institutes of the Christian Religion (1559) - John Calvin
Book 2 - God the Redeemer
Chapter 12 - Christ had to become Man in Order to Fulfill the Office of Mediator
Sections 1-3 - Reasons why it was necessary that the Mediator should be God and should become man
Section 1 - Only he who was true God and true man could bridge the gulf between God and ourselves
God decreed this necessity, not some natural law apart from God.
No man could mediate, as all are sinners - Gen 3:8.
So God had to come down to be with us - Isa 7:14; Matt 1:23.
1 Tim 2:5; Heb 4:15.
Section 2 - The Mideator must be true God and true man
His task was to make men the children of God once again.
He took on our nature - Eph 5:29-31; Gen 2:23-24 -
to give to us what was His: sonship with God - John 20:17; Rom 8:17.
Only the author of life could swallow up death.
Only the righteous one could conquer sin.
Only a power above worlds and principalities could defeat them.
Section 3 - Only the God-man could be obedient in our stead
He could only pay the penalty of death in human flesh;
He could only conquer that death in divine power.