They discussed this among themselves and said, “If we say ‘Of heavenly origin,’ he will say to us, ‘Then why did you not believe him?’
But if we say, ‘Of human origin,’ we fear the crowd, for they all regard John as a prophet.”
So they said to Jesus in reply, “We do not know.”
He himself said to them, “Neither shall I tell you by what authority I do these things.”
-- Mt 21:23-27
The authority required by the moral order derives from God: "Let every person be subject to the governing authorities. For there is no authority except from God, and those that exist have been instituted by God. Therefore he who resists the authorities resists what God has appointed, and those who resist will incur judgment."
-- CCC 1899
Image: Saint John of the Cross. Source: Wikipedia.