﴿ لَا يَسْتَطِيعُونَ نَصْرَهُمْ وَهُمْ لَهُمْ جُندٌۭ مُّحْضَرُونَ ﴾

“they are unable to succour their devotees, even though to them they may [appear to] be hosts drawn up [for succour].”

(It is not in their power to help them) the idols are unable to save them from Allah's chastisement; (but they) i.e. the disbelievers of Mecca (are unto them) in falsehood (a host in arms) like slaves standing before the idols.