"And, behold, I come quickly; and my reward is with me, to give every man according as his work shall be." (Revelation 22:12)
Although the Scriptures teach clearly that it is "not by works of righteousness which we have done, but according to his mercy he saved us" (Titus 3:5), they do teach that we are "created in Christ Jesus unto good works" (Ephesians 2:8-10).
Good works will never produce salvation, but they will produce heavenly rewards. "The fire shall try every man's work of what sort it is. If any man's work abide . . . he shall receive a reward" (1 Corinthians 3:13-14). Note that the criterion is not how much a man's work may accomplish, but what sort it is.
The greatest reward could well be the joy of hearing the Lord Jesus say to us at His judgment seat: "Well done, thou good and faithful servant: . . . enter thou into the joy of thy lord" (Matthew 25:21).
But if we wonder just what the particular reward will be, perhaps our text may give us a clue. Remember that, in the ages to come, His servants shall serve Him (Revelation 22:3). There will be work to do! Not drudgery or sweaty labor, but glorious work, enjoying God's great creation and helping in the accomplishment of His holy purpose in creation. In an infinite universe, with endless time, we can never run out of useful, rewarding work to do, as we serve Him.
He says He will "give every man according as his work shall be." Perhaps this suggests that our work here, with the interests and abilities God has given us, will have some relation to our work there, using those same interests and abilities. In any case, we can be confident that our "labour is not in vain in the Lord" (1 Corinthians 15:58). HMM