Albert Barnes on Luke 17:20

Of the Pharisees. This was a matter of much importance to them, and they had taught that it would come with parade and pomp. It is not unlikely that they asked this merely in contempt, and for the purpose of drawing out something that would expose him to ridicule.

The kingdom of God. The reign of God; or the dispensation under the Messiah. Mt 3:2.

With observation. With scrupulous and attentive looking for it, or with such an appearance as to attract observation--that is, with pomp, majesty, splendour. He did not deny that, according to their views, the time was drawing near; but he denied that his kingdom would come in the manner in which they expected. The Messiah would not come with pomp like an earthly prince; perhaps not in such a manner as to be discerned by the eyes of sagacious and artful men, who were expecting him in a way agreeable to their own feelings. The kingdom of God is within men, and it makes its way, not by pomp and noise, but by silence, decency, and order, 1Cor 14:40.