Now you know what is restraining him, to the end that he may be revealed in his own season.
Withholdeth -- restrains him. A restrain upon the appearance of the "man of sin." While Nero’s teacher Seneca lived, he had a restraining influence upon him. But after Nero put him to death he became a very different ruler (see note Nero, in v. 3 2 Thessalonians 2:3 ) "The glorious first five years of Nero’s reign (54-59) under the wise guidance of Seneca and Burrhus, make the other nine (59-68) only more hideous by contrast."