Tafsir of Ya seen 36:28

{And We did not send down upon his people}—that is, the people of the man who was told, "Enter Paradise"—{after him}—that is, after his killing; it is also said: after he was raised alive to the heaven—{any troops}—meaning an army. The min (preposition) is used for the reinforcement of the negation. It is also said that it may denote partition, though that is contrary to the apparent meaning. The jund (troops) refers to a military force due to its severity, as if it were derived from jand—hard, rocky earth. The apparent meaning is that what is intended by this "troops" is an army of angels; that is, We did not send down angels from the heaven to destroy them.

{And We were not to send down}—it was not consistent with Our wisdom to send down troops for their destruction, because We have ordained a cause for everything. We destroyed some of the nations by a rain of stones, some by a blast, some by causing the earth to swallow them, and others by drowning. We made the sending down of troops a privilege specific to you, to grant you victory over your people, and We sufficed against those [people of the man] with a single blast from an angel who shouted at them, and they perished, as He, the Exalted, said:...