True peace of mind is rarely purchased with material wealth; rather, it often blossoms from simple, honest labor, while vast possessions can become a source of endless anxiety. The primary approach among commentators focuses on the daily life of a simple farm worker or laborer. The sleep of such a person is deep and sweet, regardless of whether he eats a little or a lot. His natural fatigue and physical exertion bring about restful sleep, entirely independent of his food intake [רש״י, מצודת דוד, ביאור שטיינזלץ, צאינה וראינה]. In stark contrast, an abundance of property robs the wealthy man of his rest. His mind is constantly plagued by thoughts of his many businesses and the lingering fear that his fortune might be lost to robbers or the authorities [רש״י, מצודת דוד, אבן עזרא, צאינה וראינה]. Beyond mental anxiety, the wealthy man's insomnia may also stem from a lack of physical exertion, as his body is simply not tired enough to rest [ביאור שטיינזלץ], or from the physical discomfort brought on by overeating [אבן עזרא].
Beyond the simple realities of daily work, this dynamic applies to the realms of leadership and spiritual devotion. A person rich in greatness and honor, such as a public leader, often finds no rest. The endless needs of the community constantly burden his mind, denying him the peaceful sleep enjoyed by his simple, worry-free servants [תורה תמימה]. In the realm of serving God, the laborer represents anyone dedicated to spiritual work. Whether a person manages to accomplish a little or a lot—such as bringing offerings or engaging in general service to God—the quantity matters far less than the intention. As long as a person's heart is genuinely directed toward heaven, he will receive his reward and rest without fear [תורה תמימה].
The concept of restful sleep is also deeply connected to death and the afterlife. For the righteous, the sleep of death is sweet, as they receive their full reward in the World to Come regardless of how long they lived. Just as the prophet Samuel's brief years of leadership are considered equal to the many years of Moses, a young scholar might achieve in a few short years what takes others an entire lifetime to learn [רש״י, תורה תמימה, צאינה וראינה]. Conversely, the wicked person who enjoyed a life of abundance and satisfaction in this world finds no peace after death. His superficial satisfaction is replaced by restlessness, as he suffers and bears the punishment for his sins [תעלומות חכמה].
Interestingly, the sleeplessness of the wealthy is not always viewed as a negative consequence. In a completely different light, the rich man represents a scholar who is deeply saturated with the wisdom of the Torah. Even after passing away, this spiritual wealth prevents him from simply resting in his grave. Instead, his lips continue to move and speak whenever his students recall his insights and teachings in this world, granting him an eternal, active presence [רש״י, צאינה וראינה].