أَلَا أَيُّهَا اللَّيْلُ الطَّوِيلُ أَلَا انْجَلِي
O long night, would that you pass away.
The poet addresses the long night with injalī (“clear away!”). Night is not an ordinary agent that can obey a command. The form conveys tamannī, an intense wish for a desired condition beyond the speaker’s directive power.
Imperative morphology dramatizes longing: the speaker desperately wants the darkness to end, but cannot literally instruct the night as one instructs a human listener. The mismatch between addressee and voluntary compliance is the clue.