2 The earth restored is the resurrection of the flesh; for after His resurrection, all those things which are sung of in the Psalm were done. Let us then hear a Psalm full of joy on the restoration of the Earth. Let the Lord our God excite in us a hope and a pleasure worthy of so great a thing; may He rule our discourse, that it be fit for your hearts, that whatever joy our heart does feel in such sights, He may bring on to our tongue, and thence conduct it into your ears, then to your heart, thence to your actions.
3....“The Lord is King, let the earth be glad: yea, let the multitude of the isles be joyous”. It is so indeed, because the word of God has been preached not in the continent alone, but also in those isles which lie in mid sea: even these are full of Christians, full of the servants of God. For the sea does not retard Him who made it. Where ships can approach, cannot the words of God? The isles are filled. But figuratively the isles may be taken for all the Churches. Why isles? Because the waves of all temptations roar around them. But as an isle may be beaten by the waves which on every side dash around it, yet cannot be broken, and rather itself does break the advancing waves, than by them is broken: so also the Churches of God, springing up throughout the world, have suffered the persecutions of the ungodly, who roar around them on every side; and behold the isles stand fixed, and at last the sea is calmed.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)