Out of deep despair, Job curses the very moment of his creation. He wishes for that specific time to be entirely erased from the fabric of existence, swallowed by absolute darkness, and left without a trace on the human calendar. Commentators agree that this refers specifically to the night he was conceived in his mother's womb [מצודת דוד, מלבי״ם, אלשיך, ביאור שטיינזלץ].
He asks for a heavy darkness to take over and claim this night for itself [מצודת דוד]. While ordinary darkness is a natural event that happens every evening, the darkness Job calls for is much thicker and far worse [מצודת ציון, מלבי״ם]. It is a state of complete void, entirely lacking any glow or moonlight [מלבי״ם]. However, another perspective suggests that this is simply a poetic repetition, viewing ordinary darkness and this heavy gloom as the exact same thing [תקות אנוש].
The desire to erase this night involves removing it from the flow of time, a concept understood in a few different ways. The primary approach among commentators is that the night should be denied any connection to the other days. It should not unite with them or be counted among them [מצודת דוד, מצודת ציון, מנחת שי, אבן עזרא]. Because a full day is formed by joining evening and morning, the curse asks that this night be severed from the day that follows, failing to complete a full daily cycle [מלבי״ם, אלשיך]. Another view suggests the idea of joy, meaning the night should be stripped of the happiness of being counted as part of the year [רש״י, אבן עזרא]. A third approach focuses on boundaries, proposing that the night should fall outside the natural definitions and laws of time that govern all other nights [תקות אנוש].
Building on this removal from time, Job wishes for the night to be completely excluded from both the solar and lunar calendars. It should not be counted among the 365 days of the solar year, nor included in the tally of nights that make up the lunar months [מלבי״ם, ביאור שטיינזלץ]. Since time itself is constructed from days and months, removing it from these counts effectively deletes this piece of time from reality [תקות אנוש]. To emphasize this void, the curse asks that the night remain completely pitch black, similar to the final nights of a lunar month when the moon offers no light at all [מלבי״ם].
Erasing a night from reality carries massive cosmic consequences. Canceling a segment of time recalls the year of the great flood, a period when the constellations did not function in their normal patterns. Furthermore, every night features shifts of angels who sing and praise before God. Wiping this night from existence means silencing that angelic song directed at Him. Yet, in the depths of his immense suffering, Job argues that this is just one single, lonely night. He feels it is entirely justified to cancel it to prevent his own creation, even if the heavy price is the loss of the angels' song to God [אלשיך].