Tafsir of Al-Isra 17:108

And they say, "Exalted is our Lord"—that is, in their prostration or absolutely—"far removed is our Lord from breaking His promise," or "from the disbelief and denial committed by the disbelievers."

"Indeed, the promise of our Lord is surely to be fulfilled." Inna (Indeed) is the mukhaffafah (lightened) form of the muthaqqalah (heavy/emphatic inna), its subject is the implicit pronoun of the state/matter (dameer al-sha'n), and the lam is the fariqah (distinguishing particle); meaning: the matter is that this [promise] is surely fulfilled.