Sing, O heavens; and be joyful, O earth; and break forth into singing, O mountains: for the Lord hath comforted his people, and will have mercy upon his afflicted. (Isaiah 49:13)
So sweet are the comforts of the Lord, that not only the saints themselves may sing of them, but even the heavens and the earth may take up the song. It takes something to make a mountain sing; and yet the prophet summons quite a choir of them. Lebanon, and Sirion, and the high hills of Bashan and Moab, He would set them all singing because of Jehovah’s grace to His own Zion. May we not also make mountains of difficulty, and trial, and mystery, and labor become occasions for praise unto our God? “Break forth into singing, O mountains!”
This word of promise, that our God will have mercy upon His afflicted, has a whole peal of bells connected with it. Hear their music—”Sing!” “Be joyful!” “Break forth into singing.” The Lord would have His people happy because of His unfailing love. He would not have us sad and doubtful; He claims from us the worship of believing hearts. He cannot fail us: why should we sigh or sulk as if He would do so? Oh, for a well-tuned harp! Oh, for voices like those of the cherubim before the throne!
C.H. Spurgeon, Faith’s Checkbook