And ever is Allah, of what
وَكَانَ اللَّهُ بِمَا تَعْمَلُونَ [Al-Ahzab 33:9]
"With the taa from digging the trench, and with the yaa from the plotting of the polytheists" means there are two readings in it:
of what they do
بما يعملون
and
of what you do, is Seeing
بما تعملون بَصِيرًا [Al-Baqarah 2:265-266]
His saying:
and We sent upon them a wind
فَأَرْسَلْنَا عَلَيْهِمْ رِيحًا [Al-Ahzab 33:9]
What is this wind? I told you it is the eastern wind, and that is why it came in the hadith:
I have been helped by the east wind and the 'Ad were destroyed by the west wind.
نصرت بالصبا وأهلكت عاد بالدبور Sahih Muslim 900a The Dabur is the western wind. Yes, he says:
of what you do
بما تعملون
"With the taa from digging the trench" but this specification of the verse is not appropriate. Take note of this. Why is it not appropriate? Because if we specify the generality in the verse, we restrict the meaning of the word, or we restrict the word to part of its meaning. The correct view is that it is
of what they do
بما تعملون
from digging the trench and everything else you did in this expedition.
Seeing
بصير
That is, All-Knowing, or
of what they do
بما يعملون
meaning the armies.
when armies came to [attack] you
إِذْ جَاءَتْكُمْ جُنُودٌ [Al-Ahzab 33:9]
So Allah the Exalted was Seeing of what they did, regarding their plotting against the Prophet (peace and blessings be upon him) and their coming to the land of the Messenger (peace and blessings be upon him) in order to eliminate him, as they claimed.