Facing the reality of a limited lifespan, a person naturally seeks the spiritual tools needed to use their time properly and avoid sinking into meaningless pursuits. This plea to God involves both an honest recognition of life's fleeting nature and the moral and intellectual growth that comes from such awareness.
The primary approach among commentators is that this is a request for God to grant us the understanding to truly internalize how short and temporary life is [אבן עזרא, רד״ק, מאירי, ביאור שטיינזלץ]. Recognizing that death is always approaching wakes a person up to repent every single day. It encourages individuals to carefully calculate their remaining years and stop chasing after worthless things that offer only short-lived benefits [אלשיך, ביאור שטיינזלץ].
While this is the main understanding, there are other ways to view this plea. Some explain it as a request regarding suffering, asking God to ensure that any punishments or rebukes are kept small, matching the very short span of our lives [רש״י, מאירי]. Another perspective suggests that precisely because our time is so brief, we ask God to shower us with a massive amount of wisdom in the little time we have [מצודת דוד]. In complete contrast, others view this as a request for a long life, asking God to make it known in the world that we will live for many years, thereby giving us ample time to acquire true wisdom [רש״י].
The ultimate goal of recognizing the value of time is to draw wisdom inward. This outcome is the direct result of God teaching us to properly measure our days [רש״י, אבן עזרא, מצודת ציון, מלבי״ם]. Such wisdom takes practical shape as a deep desire to immerse oneself in the Torah [מצודת דוד]. It also provides the ability to unite both the good and evil inclinations, channeling the entirety of the human heart toward serving and fearing God [אלשיך].
Beyond the individual, this plea also applies to the national experience during the period of exile. In this light, it is a cry for God to reveal the hidden end date of the long and painful exile [רד״ק, מאירי]. The request for wisdom here transforms into a request for a prophet. The nation asks God to reveal when a prophet will finally be sent to straighten their path and bring them a wise heart [רד״ק, מאירי]. This connects to the tradition that ever since the destruction of the Temple, the power of prophecy was transferred from the prophets to the wise. Therefore, a wise person is considered greater than a prophet, as the wise continue to carry the combined spirit of both prophecy and wisdom within them [תורה תמימה].