The term translated as “dominion” means power, rule
and so implies the presence of strength. Peter had used the word in 1 Peter 5:6 when he spoke about the need to be humble under “the mighty hand of God” (and hinted at it when he described the devil as “roaring lion”). Though the opposition the Christian encounters in this world may seem too much (after all, Christians are martyred), power belongs ultimately to God so that he is mighty to deliver in surprising ways (Acts 12:7) or perhaps use the opposition to bring his own to glory (as church history records happened to Peter himself). This is a power that God has irrevocably and therefore eternally.
11 To him be the dominion forever and ever. Amen.