Adam Clarke on John 18:36

My kingdom is not of this world - It is purely spiritual and Divine. If it had been of a secular nature, then my servants would have contended - they would have opposed force with force, as the kingdoms of this world do in their wars; but as my kingdom as not of this world, therefore no resistance has been made. Eusebius relates, Hist. Eccles. lib. iii. c. 20, that "The relatives of our Lord were brought before Domitian, and interrogated whether they were of the family of David; and what sort the kingdom of Christ was, and where it would appear? They answered, that this kingdom was neither of this world, nor of an earthly nature; that it was altogether heavenly and angelical; and that it would not take place till the end of the world."