After all of the signs and miracles that Jesus did in the presence of these religious elite, and after HIS harsh rebuttal of their stubborn and blasphemous hearts, the Scribes and Pharisees who had been rebuked by Jesus for blasphemy had the audacity to ask for a sign from Jesus to prove to them who he was ... a sign to prove to them that Jesus himself was not blasphemous, not from Beelzebub.
How Jesus responds to these men reveals much about how Jesus is always LORD ... even when more is demanded of him.