Mark 11:31-33
11:31 They discussed with one another, saying, “If we say, ‘From heaven,’ he will say, ‘Then why did you not believe him?’
11:32 But if we say, ‘From people – ’” (they feared the crowd, for they all considered John to be truly a prophet).
11:33 So they answered Jesus, “We don’t know.” Then Jesus said to them, “Neither will I tell you by what authority I am doing these things.”