It was recited as يُنَزِّلُ with both lightening and intensifying. And it was recited تَنَزَّلُ الْمَلائِكَةُ, meaning they descend with the Spirit by His command, bringing to life the dead hearts through His revelation, or what serves in religion as the Spirit does in the body. And أَنْ أَنْذِرُوا is a substitute for the Spirit, meaning He brings them down by saying, 'An admonition.' Its estimation is: by saying, 'I say to you, admonish.' Or 'أن' could be explanatory, because the descent of the angels with revelation contains the meaning of saying.

The meaning of 'admonish' is that there is no deity except Me. Inform them that this is the matter, as I have warned you of such. The meaning is: He says to them, 'Inform the people of My saying, there is no deity except Me, so fear Me.'