'In the beginning was the Word, and the Word was with God, and the Word was God.'
John 1:1
Jesus was not just a man sent from God, He was God.
This is the most important statement of the New Testament. On this truth hangs all other truths.
If Jesus was only a man, then regardless of how good He was, His life could only provide a substitute for one other man. But since He was God, His life was worth more than every human life since creation. Indeed it was worth more than the sum total of the universe that He created.
Any compromise on this point will negate the work of Christ in our lives. Jesus was God manifest in the flesh (1 Tim. 3:16)!