After Satan has God's sentence carried out against him, then a process of judgment begins. It begins in what we call the Millennium and continues right through what we call the Great White Throne period. The judgment spoken of in Matthew 12:41-42 is that of the Great White Throne, during which the act of evaluation, by God, of those people who are living at that time takes place.
John W. Ritenbaugh
Fall Feast Lessons
The men of Nineveh will rise up in judgment and condemn the people of Jesus' generation because they did not respond to the message of repentance He brought. Then He says the queen of the South, the Queen of Sheba, will also condemn this generation because they did not understand the wisdom that Jesus brought—wisdom far greater than Solomon's.
Richard T. Ritenbaugh
Parables of Matthew 13 (Part 2): Leaven
Other Forerunner Commentary entries containing Matthew 12:41: