وَكُلُّ مَاءٍ دَائِمٍ إِذَا وَقَعَتْ فِيهِ نَجَاسَةٌ لَمْ يَجُزِ الْوُضُوءُ بِهِ، قَلِيلًا كَانَ أَوْ كَثِيرًا؛ لِأَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَمَرَ بِحِفْظِ الْمَاءِ مِنَ النَّجَاسَةِ، فَقَالَ:
Meaning: If impurity falls into stagnant water, wudu from it is not permissible, whether its quantity is small or large, for the Prophet ﷺ instructed that water be protected from impurity, saying:
Ma' da'im means water that stands still rather than flows. The passage gives a general prohibition where impurity enters stagnant water.
The subsequent rule of a very large pond provides a specific qualification; the wording “small or large” should be read together with that later distinction.