7 While you are rejoicing, and delighted with the ductile trumpets, and the voice of the horn, what follows? “Let the sea be stirred up, and the fullness thereof”. Brethren, when the Apostles, like ductile trumpets and horns, were preaching the truth, the sea was stirred up, its waves arose, tempests increased, persecutions of the Church took place. Whence has the sea been stirred up? When a joyful noise was made, when Psalms of thanksgiving were being sung before God: the ears of God were pleased, the waves of the sea were raised. “Let the sea be stirred up, and the fullness thereof: the round world, and all that dwell therein.” Let the sea be stirred up in its persecutions. “Let the floods clap their hands together”. Let the sea be aroused, and the floods clap their hands together; persecutions arise, and the saints rejoice in God. Whence shall the floods clap their hands? What is to clap their hands? To rejoice in works. To clap hands, is to rejoice; hands, mean works. What floods? Those whom God has made floods, by giving them that Water, the Holy Spirit. “If any man thirst,” says He, “let him come unto Me, and drink. He that believes in Me, out of his bosom shall flow rivers of living water.” These rivers clapped their hands, these rivers rejoiced in works, and blessed God. “The hills shall be joyful together.”
8. “Before the Lord, for He has come; for He has come to judge the earth”. “The hills” signify the great. The Lord comes to judge the earth, and they rejoice. But there are hills, who, when the Lord is coming to judge the earth, shall tremble. There are therefore good and evil hills; the good hills, are spiritual greatness; the bad hills, are the swelling of pride. “Let the hills be joyful together before the Lord, for He has come; for He has come to judge the earth.” Wherefore shall He come, and how shall He come? “With righteousness shall He judge the world, and the people with equity”. Let the hills therefore rejoice; for He shall not judge unrighteously. When some man is coming as a judge, to whom the conscience cannot lie open, even innocent men may tremble, if from him they expect a reward for virtue, or fear the penalty of condemnation; when He shall come who cannot be deceived, let the hills rejoice, let them rejoice fearlessly; they shall be enlightened by Him, not condemned; let them rejoice, because the Lord will come to judge the world with equity; and if the righteous hills rejoice, let the unrighteous tremble. But behold, He has not yet come: what need is there they should tremble? Let them mend their ways, and rejoice. It is in your power in what way you will to await the coming of Christ. For this reason He delays to come, that when He comes He may not condemn you. Lo, He has not yet come: He is in heaven, thou on earth: He delays His coming, do not thou delay wisdom. His coming is hard to the hard of heart, soft to the pious. See therefore even now what you are: if hard of heart, you can soften; if you are soft, even now rejoice that He will come. For you are a Christian. Yea, you say, I believe that you pray, and sayest, “Your kingdom come.” You desire Him to come, whose coming you fear. Reform yourself, that you may not pray against yourself.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)