As for “that night.” Job, having cursed the day, proceeds to utter a malediction on the “night” also; see Job 3:3. This malediction extends to Job 3:9.
Let darkness seize upon it - Hebrew, Let it take it. Let deep and horrid darkness seize it as its own. Let no star arise upon it; let it be unbroken and uninterrupted gloom. The word “darkness,” however, does not quite express the force of the original. The word used here אפל 'ôphel is poetic, and denotes darkness more intense than is denoted by the word which is usually rendered “darkness” השׁך chôshek. It is a darkness accompanied with clouds and with a tempest. Herder understands it as meaning, that darkness should seize upon that night and bear it away, so that it should not be joined to the months of the year. So the Chaldee. But the true sense is, that Job wished so deep darkness to possess it, that no star would rise upon it; no light whatever be seen. A night like this Seneca beautifully describes in Agamemnon, verses 465ff:
Nox prima coeltum sparserat stellis,
Cum subito luna conditur, stellae cadunt;
In astra pontus tollitur, et coelum petit.
Nec una nox est, densa tenebras obruit
Caligo, et Omni luce subducta, fretum
Coelumque miscet ...
Premunt tenebrae lumina, et dirae stygis
Inferna nox est.
Let it not be joined unto the days of the year - Margin, “rejoice among.” So Good and Noyes render it. The word used here יחד yı̂chad, according to the present pointing, is the apocopated future of חדה chādâh, “to rejoice, to be glad.” If the pointing were different יחד yâchad it would be the future of יחד yachad, to be one; to be united, or joined to. The Masoretic points are of no authority, and the interpretation which supposes that the word means here to exult or rejoice, is more poetical and beautiful. It is then a representation of the days of the year as rejoicing together, and a wish is expressed that “that” night might never be allowed to partake of the general joy while the months rolled around. In this interpretation Rosenmuller and Gesenius concur. Dodwell supposes that there is an allusion to a custom among the ancients, by which inauspicious days were stricken from the calendar, and their place supplied by intercalary days. But there is no evidence of the existence of snell a custom in the time of Job.
Let it not come etc - Let it never be reckoned among the days which go to make up the number of the months. Let there be always a blank there; let its place always be lacking.