8. The figurative meaning of the number “one thousand.”
There is good biblical reason to believe that the number “one thousand” as used here is figurative rather than literal. [Earlier in this book we have] seen that the numbers in Revelation are symbolic in nature. The use of “signify” (NASB mg.; Greek sēmainō) in 1:1 with reference to the whole book encourages the reader to expect a predominance of symbolic over literal language, including references to numbers (see on 1:1).
The Bible also uses this particular number figuratively: “He has remembered His covenant forever, the word which He commanded to a thousand generations” (Ps. 105:8; see 1 Chron. 16:15). Ps.90:4 should probably be taken figuratively (as a reference to a long period of time),”For a thousand years in Thy sight are like yesterday when it passes by.” The same is true in 2 Pet. 3:8, “With the Lord one day is as a thousand years, and a thousand years as one day” (for further references see on v.4 above). It may be used as a contrast with the brief period of conflict immediately before the Lord’s return, which is “three and a half days in 11:11 and one hour in
“One thousand” also signifies the idea of completeness in Revelation, as in the measurements of the eternal city in 21:16, where “twelve thousand stadia” represents the number of God’s people (twelve) multiplied by one thousand, in order to express the completeness of that people. “One thousand years” would thus signify the complee duration of the church age. Multiples of one thousand have previously been used figuratively in Revelation (see on 7:4-9; 9:16; 14:1; cf.5:11) to express either a large number, a complete number, or both. It does not necessarily signify a very long period of time (however we might construe that), but points more to the idea of a fullness of time allowed by God’s sovereignty at the end of which will surely come the ultimate victory of Christians who have suffered.
We have already suggested that if the suffering saints persevere through their short trials of “ten days” (2:10), they will be given the reward of a millennial reign. The intensifying of ten to a thousand (one thousand being ten to the third power), together with the lengthening of days to years, might suggest that momentary affliction in the present results in a far greater glory even in the intermediate state prior to eternal glory.
-G. K. Beale with David Campbell, Revelation: A Shorter Commentary, 446.