Matthew 8:12

“But the sons of the Kingly Rule will be cast forth into the outer darkness. There will be the weeping and the gnashing of teeth.”

This contrast confirms that Gentiles were in mind in the previous verses. For here the ‘sons of the Kingly Rule', that is those who outwardly appeared to have a right to the enjoyment of that Kingly Rule and indeed laid a claim to it, signifies the Jews. (Compare ‘sons of Belial' which meant those who connected themselves with Belial, ‘sons of the bridechamber' which indicated those who connected themselves with the bridegroom). Outer darkness signifies being away from the inner circle of the light of God, having been cast from His presence into the outer darkness. (Compare Psalms 88:6; Isaiah 47:5; Isaiah 60:2). Darkness was regularly a picture of the Lord's judgments (Isaiah 47:5; Joel 2:31; Amos 5:18; Amos 5:20; Nahum 1:8; Zephaniah 1:15). It was from the darkness that Jesus had come to deliver His people (Matthew 4:16). But now He informs them that while many Gentiles will come to His light (compare Isaiah 42:6; Isaiah 49:6), many Jews who thought themselves secure will be cast from it. The weeping and gnashing of teeth indicates the shock, horror and anguish that they will suffer as a result. It is a picture of despair, anger, incredulity and hopelessness all rolled into one (compare Matthew 13:42; Matthew 13:50; Matthew 22:13; Matthew 24:51; Matthew 25:30; Psalms 112:10). For it will be the opposite of what in their view was supposed to happen (Isaiah 60:2). Darkness was intended for the Gentiles, not for the Jews (Wisdom of Solomon Matthew 17:17; Matthew 17:21). But now being children of Abraham will have done them no good as John had warned them (Matthew 3:9), because they had turned from their Messiah. A similar idea is found in John 3:18.

Note the threefold, ‘cast into outer darkness', ‘weeping', ‘gnashing of teeth' and compare it with ‘lies in the house', ‘sick of the palsy', ‘grievously tormented'. The one is delivered by the powerful word of Jesus from misery, the others are sentenced by that same word to misery (John 12:48).

Some see the picture as illustrating their being kept out of the brilliantly lit banqueting hall of the Messianic Banquet, and thrown out into the darkness outside. But that is probably to limit too much its deliberately universal and eschatological scope.