How do we know that Christ's return is a day of judgment?

The certainty of Christ's return as a day of judgment is affirmed throughout scripture, notably in Revelation 6:15-17, where individuals from all walks of life attempt to hide from the face of Him who sits on the throne and the wrath of the Lamb. Their desperate cry reflects their awareness of their guilt and the impending judgment they face. This aligns with Jesus’ teachings in various passages, such as Matthew 25:31-46, where the separation of the sheep from the goats illustrates the final judgment that will occur. In this light, the day of Christ's return is not merely a day of reckoning but is fundamentally a demonstration of God's justice and holiness, ultimately vindicating His people and displaying His authority over creation.