J.R. Miller emphasizes the necessity of keeping our lives in tune, much like a piano requires regular tuning to avoid discord. He explains that life's experiences can exhaust us, making it essential to seek spiritual renewal through communion with God, especially after a long day. Miller illustrates that just as a piano can fall out of tune through disuse or misuse, our lives can also become discordant through neglect or sin. He encourages us to align our lives with God's will, as true harmony comes from obedience and love. Ultimately, the goal is to submit our lives to God, allowing His grace to help us create beautiful music in our daily existence.