Jamieson, Fausset and Brown on Revelation 2:26

26. And--implying the close connection of the promise to the conqueror that follows, with the preceding exhortation, Re 2:25.

and keepeth--Greek, "and he that keepeth." Compare the same word in the passage already alluded to by the Lord, Ac 15:28, 29, end.

my works--in contrast to "her (English Version, 'their') works" (Re 2:22). The works which I command and which are the fruit of My Spirit.

unto the end--(Mt 24:13). The image is perhaps from the race, wherein it is not enough to enter the lists, but the runner must persevere to the end.

give power--Greek, "authority."

over the nations--at Christ's coming the saints shall possess the kingdom "under the whole heaven"; therefore over this earth; compare Lu 19:17, "have thou authority [the same word as here] over ten cities."