2 Thessalonians 1:5

which is a manifest token of the righteous judgment of God; to the end that ye may be counted worthy of the kingdom of God, for which ye also suffer:

Token of the righteous judgment of God ... All of the sufferings of God's people inflicted upon them by unbelievers and enemies of righteousness will be vindicated in the righteous judgment of Almighty God against such offenders; and so certain is that judgment (about which Paul will momentarily speak) that the very persecutions themselves are actually a token of the judgment to come.

Counted worthy ... It is worth noting that the RSV "is mistaken in translating this made worthy."[13] "Paul did not mean that they would be refined by suffering in a kind of earthly purgatory and therefore be able to stand in their own purity at the judgment."[14]

Kingdom of God ... This cannot possibly mean that the Thessalonians were not in the kingdom of God. Paul had specifically stated to them that they were "in Christ" (1 Thessalonians 1:1), and no man was ever in Christ without being in the kingdom of God and of Christ. Paul simply meant by this that their fidelity through sufferings would make and prove their worthiness of being in the kingdom.

[13] Peter E. Cousins, op. cit., p. 499.

[14] Ronald A. Ward, op. cit., p. 140.