10:5 And the angel whom I saw standing on the sea and on the land lifted up his right hand to heaven,
And the ANGEL whom I saw standing on the SEA and on the LAND
This is the strong ANGEL in verse 2.
lifted up his RIGHT HAND to HEAVEN.
The context of this whole chapter (interlude) is that John is on the earth because he sees the strong angel coming down out of heaven and now, the RIGHT HAND is lifted upwards to HEAVEN. It is raised to take an oath. This is an Old Covenant act, Deuteronomy 32:40-43. The strong angel's oath is in the succeeding verses. Compare this verse with Daniel 12:5-13.
In this church age, taking an oath is NOT something we are to do. Jesus said so in Matthew 5:33-37. Therefore, this act which gives the strong angel the authority to perform the judgment he is about to do, is an Old Covenant act. Apparently, the government of heaven, at least with respect to heaven and all of the created universe, is like that explained in the Old Testament. We, the redeemed, again, fit into heaven because of the unique act of Jesus Christ's death.