"They cannot help them," meaning: their gods which they worship cannot help them, "and they will be brought forward as a host for them," meaning: they will be with them in the Fire; according to the interpretation of Qatadah.
﴿لَا يَسْتَطِيعُونَ نَصرهم﴾ لَا تَسْتَطِيع آلِهَتهم الَّتِي يعْبدُونَ نَصْرَهُمْ ﴿وَهُمْ لَهُمْ جُنْدٌ مُحْضَرُونَ﴾ مَعَهم فِي النَّار؛ فِي تَفْسِير قَتَادَة