2 Thessalonians 2:6

And now ye know that which restraineth, to the end that he may be revealed in his own season.

That which restraineth ... This is viewed generally, by nearly all schools of interpreters, as being the Roman government. This is supported by the context in that it would explain why Paul spoke so guardedly of its being taken out of the way." However, the prophecy reaches far beyond the fall of the ancient empire; and the best view of this is, in all probability, that of Hendriksen:

Of all the theories advanced so far, the one which seems to have most in its favor is that in which the restrainer is "the power of well-ordered human rule," or as Ellicott's Commentary has it, "the principle of legality as opposed to that of lawlessness."[4]

The principle of law and order, as enforced by human authority, is "that which restraineth" until he be taken out of the way. This means that Satan will continually use every device, pursue every opportunity, and employ every diabolical instrument in his efforts to break down law and order in society.

Hence, for the time being, the worst Satan can do is to promote the spirit of lawlessness. But this does not satisfy him. It is as if he and his man of sin bide their time. At the divinely decreed moment (the appropriate time) when, as a punishment for man's willingness to cooperate with this spirit, the "someone" and "something" that now holds back is removed, Satan will begin to carry out his plans.[5]

[4] William Hendriksen, op. cit., p. 181.

[5] Ibid., p. 183.