From Howe's Battle Hymn. The First Draft, The Final Version:

6. "He is coming like the glory of the morning on the wave...." - Julia eliminated this verse from her poem because she felt it detracted from the drama of the fifth verse. It has since been restored in some versions of the song, such as that in the Methodist hymnals. To my knowledge, no one has ever tried to analyze it before. The verse continues the "second advent" theme started in the first verse. Although I cannot speak with certainty about the possible source of inspiration for the first two lines of this verse, they seem to be an outgrowth of Revelation 5:12-13: "Saying with a loud voice, Worthy is the Lamb that was slain to receive power, and riches, and wisdom, and strength, and honour, and glory, and blessing. And every creature which is in heaven, and on the earth, and under the earth, and such as are in the sea, and all that are in them, heard I saying, Blessing, and honour, and glory, and power, be unto him that sitteth upon the throne, and unto the Lamb for ever and ever." The third line is more easily identified. The first part comes from Isaiah 66:1: "The heaven is my throne, and the earth is my footstool." The second part, and here I am less certain, suggests Revelation 18:11-17 which speaks of the merchants of the earth who lament the destruction of a great city. Among other things, these merchants traffic in "slaves, and [the] souls of men." Howe seems to have turned this material inside out and invoked the lex taliones a second time, saying that the slave merchants, who are to her the "soul of wrong," will now be God's slaves. This, in turn, suggests the old Roman festival called "Saturnalia" during which masters became servants and servants ruled the household for the day. Such reversals of fortune are not unknown in the teachings of Jesus. In Mark 11:31, Jesus is reported as saying "But many that are first shall be last; and the last first."