What led Christians to this concluson?
What he did: “He went about doing good.”
What he said: “Never spoke a man thus.”
Who he was: “We beheld his glory.”
Somehow for them Jesus was transparent to God: Jesus’ love for them was experienced directly by them as God’s transforming and atoning love for them. They discovered God’s love through Jesus.
What they came to believe about him was (they were convinced) based first on their experience of him.