Horatius Bonar emphasizes the profound significance of the final judgment, where Christ, referred to as the Son of Man, will return in glory to separate the righteous from the wicked. He describes the coming of Christ as a powerful event accompanied by angels, where all nations will be gathered before Him for judgment. The sermon highlights the importance of actions taken or neglected towards others as the basis for this separation, with the righteous receiving eternal life and the wicked facing condemnation. Bonar stresses that this judgment is inevitable and will be executed without error, leading to either everlasting joy or punishment. The message serves as a call to reflect on our deeds and their eternal consequences.