Here is their answer:
*** w80 8/15 p. 14 pars. 3-4 The “Great Crowd” Renders Sacred Service Where? ***
What an honored position this “great crowd” is said to occupy, and what a dignified appearance they are said to have! Even in modern times it is proper for one to stand when in the presence of a monarch who is seated on his throne. But here those of that “great crowd” are seen standing before the throne of God himself. Also, in order to suit the occasion, they are clothed with spotless white robes. Are they seen standing in some out-of-doors gathering? No, for Revelation 7:15 (ED) says that “they . . . publicly serve him day and night in his temple [na·os´ in the Greek original text].” Well, now, does this mean that those making up this “great crowd” finally go to heaven where the God is to whom they ascribe their “salvation”? The answer generally given is Yes! Why? Because it is said to be “in his temple” (ED), or, “in his sanctuary” (Rotherham), that they render to him public service or “divine service.”
4 However, does that view fit all the detailed facts set out in the last book of the Bible, Revelation? Also, as regards those who today consider themselves part of that “great crowd” that is now being formed, do they expect to go to heaven and become spirit creatures like angels? Do they even want to go to heaven? They will tell you No! and they do not consider themselves to be begotten by God’s spirit to such a heavenly hope. The question revolves around that original Greek word that is variously translated as “tent,” “temple” and “sanctuary.” For example, in the Bible account of where Jesus Christ drove the money changers and merchantmen out of Herod’s temple, the original Greek word used is na·os´. There we read: “Jesus answered, ‘Destroy this sanctuary [na·os´], and in three days I will raise it up’. The Jews replied, ‘It has taken forty-six years to build this sanctuary [na·os´]: are you going to raise it up in three days?’ But he was speaking of the sanctuary [na·os´] that was his body.” (John 2:19-21, The Jerusalem Bible) By “sanctuary,” what did those Jews mean?