Tafsir of Ya seen 36:9

وجعلنا من بين أيديهم سدا

And We have put a barrier before them, Mujahid said, "Between them and the truth.''

ومن خلفهم سدا

and a barrier behind them, Mujahid said, "Between them and the truth, so they are confused.'' Qatadah said, "They move from one form of misguidance to another.''

فٲغشيناهم

and We have covered them up, means, `We have blinded their eyes to the truth.' Ibn Jarir said, "It was narrated from Ibn Abbas, may Allah be pleased with him, that he used to recite "Fa a`shaynahum'' (instead of Fa'aghshaynahum), from Al-`Asha (weakness of the sight, blindness), which is a complaint of the eye.''

فهم ﻻ يبصرون

so that they cannot see. means, they cannot benefit from goodness or be guided to it. Abdur-Rahman bin Zayd bin Aslam said, "Allah placed this barrier between them and Islam and Iman, so that they will never reach it,'' and he recited:

إن الذين حقت عليهم كلمة ربك ﻻ يومنون

ولو جاءتهم كل ءاية حتى يروا العذاب اﻻليم

Truly, those, against whom the Word (wrath) of your Lord has been justified, will not believe, Even if every sign should come to them, until they see the painful torment. (10:96-97) Then he said, "Whoever has been prevented by Allah, will never be able.'' Ikrimah said, "Abu Jahl said, `If I see Muhammad, I will do such and such.' Then Allah revealed:

إنا جعلنا في أعناقهم أغﻼﻻ فهي إلى اﻻذقان فهم مقمحون

وجعلنا من بين أيديهم سدا ومن خلفهم سدا فٲغشيناهم فهم ﻻ يبصرون

Verily, We have put on their necks iron collars reaching to the chins, so that their heads are raised up. And We have put a barrier before them, and a barrier behind them, and We have covered them up, so that they cannot see

فهم ﻻ يبصرون

(so that they cannot see).'' He said, "They used to say, `Here is Muhammad,' and he would say, `Where is he? Where is he?' And he would not be able to see him.'' Ibn Jarir also recorded this

وسواء عليهم أأنذرتهم أم لم تنذرهم ﻻ يومنون