And as regards those having insight among the people, they will impart understanding to the many. And they will certainly be made to stumble by sword and by flame, by captivity and by plundering, for some days.” (Daniel 11:32b, 33)

They stumbled in that they were persecuted and suffered intensely, some even being killed.

Moreover, they never stopped preaching, even if they found themselves in prison or in a concentration camp. In so doing, they ‘imparted understanding to the many.’ Despite persecution, in most lands ruled over by the king of the north, the numbers of Jehovah’s Witnesses increased. Thanks to the faithfulness of “those having insight,” an ever expanding part of the “great crowd” has appeared in those lands.​—Revelation 7:9-14.