«وَمِنْهُ أَيْ مِنَ الإِيضَاحِ بَعْدَ الإِبْهَامِ التَّوْشِيعُ»
Tawshīʿ is one form of clarification after ambiguity.
«أَنْ يُؤْتَى فِي عَجْزِ الْكَلَامِ بِمُثَنًّى مُفَسَّرٍ بِاسْمَيْنِ، ثَانِيهِمَا مَعْطُوفٌ»
A dual expression is given toward the end of the utterance and then explained by two nouns, the second coordinated with the first.
The audience initially encounters two things without knowing their identities, then receives both names. The delayed identification, not merely the enumeration, creates the rhetorical movement.