Albert Barnes Commentary Matthew 25:31

"But when the Son of man shall come in his glory, and all the angels with him, then shall he sit on the throne of his glory:" — Matthew 25:31 (ASV)

When the Son of Man, etc. This is in answer to the question that the disciples posed to Him concerning the end of the world (Matthew 24:3). That this refers to the Last Judgment, and not, as some have supposed, to the destruction of Jerusalem, appears for the following reasons:

1. From the fact that it was in answer to an express inquiry concerning the end of the world.
2. All nations were to be assembled—which did not take place at Jerusalem.
3. A separation was to take place between the righteous and the wicked—which was not done at Jerusalem.
4. The rewards and punishments are declared to be eternal. None of these things took place at the destruction of Jerusalem.

In His glory. This means in His own proper honor, with His glorified body, and as the Head and King of the universe (Acts 1:11; Ephesians 1:20–22; 1 Thessalonians 4:16; 1 Corinthians 15:24–25).

The throne of His glory. This means, in the language of the Hebrews, His glorious or splendid throne. It is not to be taken literally, as if there would be a material throne or seat of the King of Zion. It expresses the idea that He will come as a King and Judge to assemble His subjects before Him and to appoint them their rewards (2 Thessalonians 1:7; Jude 1:14; Revelation 1:7).