Chuck Smith discusses the theme of empty promises in Jeremiah 42:5, emphasizing the solemn vow made by the people to obey God's commands through Jeremiah. Despite their sincere intentions, their subsequent disobedience reveals a deeper issue of relying on their own strength rather than God's guidance. Smith warns that many today make similar empty promises to God, often seeking His approval for their own plans rather than true obedience. He highlights that God is not deceived by these promises, as He knows the true intentions of the heart. Ultimately, the sermon calls for genuine commitment to God's will rather than superficial vows.