Tafsir of Al-Isra 17:91

Or that you have a garden — a plantation whose trees conceal the open space beneath them — of date palms and grapevines. They specified these two because they were the most prevalent in those regions, alongside their high status.

And you cause rivers to gush forth — meaning you cause them to flow through it. [The prepositional phrase] is in the accusative case as an adverb of place, meaning in the middle of that garden and throughout its parts.

[Gushing] forth — abundantly. The intent is either the act of causing the rivers to flow through it when irrigating it, or the continuous maintenance of their flow, as indicated by the particle fa (implying sequence or consequence).