فَلْيَعْبُدُوا رَبَّ هَٰذَا الْبَيْتِ
So let them worship the Lord of this House. (106:3)
فَوَيْلٌ لِّلْمُصَلِّينَ الَّذِينَ هُمْ عَن صَلَاتِهِمْ سَاهُونَ
So woe to worshippers who are heedless of their prayer. (107:4–5)
In the first passage a command follows recalled blessings; in the second a warning receives its precise scope from a later qualifier. An adequate analysis must do more than merely note the presence of fāʾ: it must explain what the connective relation accomplishes in each passage.
Method of judgment: preserve the exact wording, identify syntax correctly, ground the rhetorical purpose in context, and distinguish a defensible interpretation from an exclusive proof where classical analyses differ.