Tafsir of Ar-Ra'd 13:5

{And if you are amazed} O Muhammad, at their statement denying the Resurrection, then their statement is truly amazing and worthy of being marveled at. This is because He who was capable of originating the great creations He enumerated for you, without being wearied by their creation, would find the re-creation to be the easiest and simplest of things for Him. Thus, their denial is one of the most astonishing of wonders.

{That when we are} until the end of their statement: It is permissible for it to be in the nominative case as a substitute for "their statement," or in the accusative case as the object of the verb "to say." If it is in the accusative, it is governed by what is implied by their saying: {You will indeed be in a new creation}.

{Those are the ones who have disbelieved in their Lord} Those are the ones who are complete and persistent in their disbelief.

{And those are the shackles upon their necks} This is a description of their obstinacy, similar to His saying: {Indeed, We have placed shackles on their necks} (Ya-Sin: 8), and like the verse: For them, away from guidance, are shackles and chains. Or, it is part of the threat [of punishment].

{And they hasten you for the evil before the good, while there have already passed before them the exemplary punishments. And indeed, your Lord is full of forgiveness for the people despite their wrongdoing, and indeed, your Lord is severe in penalty.}