«لِيُحِقَّ الْحَقَّ وَيُبْطِلَ الْبَاطِلَ»
So that He might establish the truth and annul falsehood.
This extract from Qurʾān 8:8 gives a purpose. The source also considers cases in which a cause, response or preceding event can be recovered from discourse, without having to express every link in the narrative.
For example, «فَانْفَجَرَتْ» (“then it gushed forth”) in the account of the rock gains its omitted causal background from the preceding instruction to strike it (Qurʾān 2:60). The narrative context, not mere word count, licenses the interpretation.