﴿ إِذِ ٱلْأَغْلَٰلُ فِىٓ أَعْنَٰقِهِمْ وَٱلسَّلَٰسِلُ يُسْحَبُونَ ﴾

“when they shall have to carry the shackles and chains [of their own making] around their necks,”

when idh has the meaning of idhā with fetters around their necks and chains wa’l-salāsilu a supplement to al-aghlālu ‘fetters’ so that the meaning is that these chains are also around their necks; or it al-salāsilu ‘chains’ is the subject the predicate of which has been omitted in other words the meaning being around their feet will be these chains — or alternatively its predicate is the following yushabūna they are dragged in other words they are dragged away by these chains.