Attention particles draw the listener toward what is said and may increase the perceived importance of a report. Forms discussed include “أَلَا”, “أَمَا” and “هَا”.
أَلَا إِنَّ الْحَقَّ وَاضِحٌ
Take notice: the truth is indeed clear.
Here alā draws attention, while inna reinforces the predication. They should not be treated as grammatically identical particles.
Essential distinction: alerting the listener and reinforcing the truth claim are different rhetorical functions, even though both may occur together in a single utterance.