فَقَالَ الْمَسْؤُولُ: إِنَّ الْمَاءَ أَمَانَةٌ، وَإِنَّ حِفْظَهُ وَاجِبٌ عَلَى الْجَمِيعِ.
The official said: “Water is a trust, and protecting it is everyone’s duty.”
The two occurrences of “inna” add emphasis. The initial statement frames water as a trust; the second draws the duty that follows. The particle alone cannot prove that every listener resisted the claim: importance, seriousness or uncertainty may also motivate emphasis.
Removing the particle keeps the basic predication but reduces explicit emphasis. Neither version is universally superior; a speaker’s need for reaffirmation, persuasion or simple notice determines the more suitable form.