How do we know that there is a last day?

The concept of a last day is firmly rooted in the teachings of Jesus and the prophetic words of the Old Testament. In John 6:39-40, Jesus explicitly states His assurance that He will not lose any of those the Father has given Him, but will raise them at the last day. Additionally, the prophets like Isaiah and Joel have foretold the coming of this day, establishing a Biblical foundation for the doctrine of the last day and supporting our confidence in it. The Scriptures consistently affirm that judgment is coming, and, importantly, that this judgment is tied to Christ’s atoning work and the salvation of His people.