Jamieson, Fausset and Brown on Revelation 3:11

11. Behold--omitted by the three oldest manuscripts and most ancient versions.

I come quickly--the great incentive to persevering faithfulness, and the consolation under present trials.

that ... which thou hast--"The word of my patience," or "endurance" (Re 3:10), which He had just commended them for keeping, and which involved with it the attaining of the kingdom; this they would lose if they yielded to the temptation of exchanging consistency and suffering for compromise and ease.

that no man take thy crown--which otherwise thou wouldst receive: that no tempter cause thee to lose it: not that the tempter would thus secure it for himself (Col 2:18).