Note that the term judge is used in a broader sense in Scripture than in our common parlance; it is often equivalent to ruler or king. This has an important bearing upon our conception of Christ returning to judge the earth at the Second Advent. The judgeship of Christ is not limited to passing sentence, but constitutes his reign as king over the earth.2
Let the high praises of God be in their mouth, and a two-edged sword in their hand, to execute vengeance on the nations, and punishments on the peoples; to bind their kings with chains, and their nobles with fetters of iron; to execute on them the written judgmentThis honor have all His saints. Praise the Lord! (Ps. Ps. 149:6-9)
Do you not know that the saints will judge the world? And if the world will be judged by you, are you unworthy to judge the smallest matters? Do you not know that we shall judge angels? How much more, things that pertain to this life? (1Cor. 1Cor. 6:2-3).
Where the tribes go up, the tribes of the Lord, to the Testimony of Israel, to give thanks to the name of the Lord. For thrones are set there for judgment, the thrones of the house of David. (Ps. Ps. 122:4-5)3
So Jesus said to them, Assuredly I say to you, that in the regeneration, when the Son of Man sits on the throne of His glory, you who have followed Me will also sit on twelve thrones, judging the twelve tribes of Israel. (Mtt. Mat. 19:28)
But you are those who have continued with Me in My trials. And I bestow upon you a kingdom, just as My Father bestowed one upon Me, that you may eat and drink at My table in My kingdom, and sit on thrones judging the twelve tribes of Israel. (Luke Luke 22:28-30)
3 The plural thrones (seats) has in view the bench of judges whose authority derives from the king (cf. Isa. Isa. 32:1). In the millennial Kingdom these seats will be occupied by co-rulers of the Messiah (Mtt. Mat. 19:28).Merrill F. Unger, Ungers Commentary on the Old Testament (Chattanooga, TN: AMG Publishers, 2002), Ps. 22:5.