Revised Standard Version prints verses 15-17 in the form of poetry. This may be effective in some languages; in others it may seem strange to have part of the elder’s answer in prose and part in poetry. See Section F of the introduction, “Translating the Revelation to John,” pages 6 and following.

Therefore: this refers to the fact that all of these people have made their robes white by washing them in the blood of the Lamb. Another way to render this is “For this reason.”

The throne of God … his temple: the language does not mean to imply that heaven has a palace (or, a throne room) and a temple also; it portrays heaven as God’s kingdom and God’s temple. For temple see 3.12. Day and night means that they stood there “unceasingly,” “unendingly,” or “continually.”

Serve: the verb means “to serve as a priest” (see 1.6; 5.10; Heb 8.4-5); it may mean “to worship” (as in 22.3).

He who sits upon the throne: as in 4.2, 9; 5.1.

Will shelter them with his presence: literally “will tent upon them.” The Greek verb, which is related to the noun “tent,” is the one used in John 1.14, where it is translated “dwelt” by Revised Standard Version; here it is followed by the preposition “upon,” so that the idea is not just of living with but of sheltering and protecting. New Jerusalem Bible and Translator’s New Testament translate “will spread his tent over them,” New Revised Standard Version “will shelter them,” or it can be “live with them.” One may also render this clause as “will be with them and protect them.”

Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on The Revelation to John. (UBS Handbook Series). New York: UBS, 1993. For this and other handbooks for translators see here .