This following is from Spurgeon's Cheque Book of the Bank of Faith from May 1:
The mountains and the hills shall break forth before you into singing, and all the trees of the field shall clap their hands. (Isaiah 55:12)
When sin is pardoned, our greatest sorrow is ended, and our truest pleasure begins. Such is the joy which the Lord bestows upon His reconciled ones, that it overflows and fills all nature with delight. The material world has latent music in it, and a renewed heart knows how to bring it out and make it vocal. Creation is the organ, and a gracious man finds out its keys, lays his hand thereon, and wakes the whole system of the universe to the harmony of praise. Mountains and hills, and other great objects, are, as it were, the bass of the chorus; while the trees of the wood, and all things that have life, take up the air of the melodious song.
When God's Word is made to prosper among us and souls are saved, then everything seems full of song. When we hear the confessions of young believers and the testimonies of well-instructed saints, we are made so happy that we must praise the Lord, and then it seems as if rocks and hills and woods and fields echo our joy-notes and turn the world into an orchestra. Lord, on this happy May Day, lead me out into thy tuneful world as rich in praise as a lark in full song.