Confronted with intense suffering and the shadow of mortality, a person naturally seeks to understand the boundaries of human existence. This plea to God is not merely a cry of pain, but a deep search for perspective on the temporary nature of life and its meaning in the face of death. On a practical level, David is asking to know exactly when he will die and how much time he has left [מצודת דוד, ביאור שטיינזלץ]. This request is born out of his severe agony. If he is destined to live for many more years, he will gather the inner strength to endure his current pain until he is healed. However, if his remaining time is short, he would rather pass away immediately from his illness than continue to suffer needlessly without hope [רד״ק, מצודת דוד, המאירי].
According to ancient tradition, this request was only partially granted. God responded that the exact lifespan of a human being is a divine secret that cannot be revealed to flesh and blood, though David was informed that his passing would eventually occur on the Sabbath day [תורה תמימה].
Beyond seeking a specific date, this appeal is also a prayer for internal guidance. Knowing when a period of hardship will end can provide profound comfort. Furthermore, understanding the brevity of life helps a person look inward, reevaluate their plans, and recognize their limits in this world [ביאור שטיינזלץ, המאירי]. The desire to know the measure of one's days is a straightforward request to understand the simple quantity of time left on earth [מצודת ציון]. The primary approach among commentators suggests that in questioning his own fleeting nature, the poet is expressing a desire to know how much longer he will remain among the inhabitants of this physical world [אבן עזרא, רד״ק, מצודת ציון, מלבי״ם]. Alternatively, this plea is seen as an expression of profound exhaustion, a humble recognition of human frailty and limitation in this life [ביאור שטיינזלץ, המאירי].
Taking a unique philosophical approach, this plea represents the internal struggle of a human being composed of two opposing realities: a physical body bound by the laws of nature, and a spiritual, eternal, and free soul. Through this lens, the request to God is an attempt to understand the essence of these two forces. The poet is asking about both his ultimate spiritual destiny and his temporary, physical existence. Caught in this deep conflict, he cries out to discover to which of these two realms—the lower physical world or the higher spiritual reality—he truly belongs [מלבי״ם].