At the link, you can click on a video or just audio of the sermon for May 2nd, "Praising God."
Psalm 148 presents the universe as a four-section choir:
Heaven (the unseen and spiritual realm), verses 1 - 2
Nature, verses 3 - 10
Humanity, verses 11 - 12
The Church, verse 14
Sin has us terribly out of tune and out of time, but in Christ we are brought together in one perfect voice of praise to God (verse 13).