In John 8, Jesus talks to some Jews, who are on his side at the beginning of the conversation. But then he starts making outrageous unfounded accusations against them, and before long they think Jesus is demon-possessed and should be stoned to death.

During that conversation, Jesus mentions these Jews doing what their father has told them. They respond that Abraham is their father. When Jesus disagrees, the Jews now insist that God is the only father they have. (Which they think somehow shows that they’re not illegitimate children.) Jesus doesn’t agree with that either, and insists the devil is their father. But forget about what Jesus thinks… How can the Jews say God is their only father, when they just said Abraham is their father?

Possible explanation

I guess Abraham must be God.