"They answer: 'We are but improving things!' (Qûlû innamâ nahnu muslihûn):"

In the substitution of "they answer (lit. say) (qâlû)" for 'they do not accept advice' (lâ yaqbulûna al-nasîha), which would have been appropriate in the context, is an indication that they are making presumptuous claims and calling others to their way.

"innamâ," [the restrictive particle, meaning only or but], possesses two characteristics:

The First: The phrase in which it is included has necessarily to signify something known, either in reality or allegedly. Thus, it infers depreciation of the one offering advice, as well as their [the dissemblers'] persisting in their compounded ignorance.

The Second: The restriction of "but" indicates that in their view their improving things is unadulterated by corruption. And this is an insinuation against the believers [who say the opposite].

The use of the active participle in "(lit.) improvers [of things] (muslihûn)" rather than the verbal form 'we are making improvements, setting in order, etc.' indicates that [they allege that] this attribute of theirs is constant and continual and that what they are doing is total betterment. But they are dissimulating in saying this also, for what they profess inwardly is the opposite of what they profess outwardly: inwardly they claim their corruption to be improving things, and outwardly they hypocritically claim that what they do is for the betterment of the believers and in their interests.

"Oh, verily, it is they, they who are who are spreading corruption, but they perceive it not. (A' lâ innahum hum al-mufsidûna wa lâkin lâ yash'urûn):"

Consider this: the previous verse inferred a number of things about the dissemblers: for example, their spreading their ideas, and claiming that they consistently put things to rights and that this is a constant attribute of theirs, and is confined to them; and that their bettering things is untouched by corruption; that this is clear and well-known; and their casting aspersions on the believers and imputing ignorance to those who offer them advice. Here, the Qur'an replies to them with the present sentence, which comprises elements proving their corruption and that they have become one with it; that corruption is restricted to them, and that this is an established fact, and warning the people against them, and showing them to be ignorant by disallowing them any senses, as though they were inanimate. If you wish, consider the following: