The Command to eat Pure Things and the Explanation of the Prohibited Things

Allah commands His believing servants to eat from the pure things that He has created for them and to thank Him for it, if they are truly His servants. Eating from pure sources is a cause for the acceptance of supplications and acts of worship, just as eating from impure sources prevents the acceptance of supplications and acts of worship, as mentioned in a Hadith recorded by Imam Ahmad, that Abu Hurayrah said that Allah's Messenger ﷺ said:

«أَيُّهَا النَّاسُ إِنَّ اللهَ طَيِّبٌ، لَا يَقْبَلُ إِلَّا طَيِّـبًا، وَإنَّ اللهَ أَمَرَ الْمُؤْمِنِينَ بِمَا أَمَرَ بِهِ الْمُرْسَلِينَ، فَقَالَ:

Earlier, the aim was to correct the error made by the mushrikin مشرکین when they made unlawful what was good and permissible. Now, in the present Verse (172), the believers are being warned against falling into the same error. As a corollary, they are reminded of Allah's blessings and are taught to be grateful to Him.

Later, in Verse 173 it is said that the prohibited must remain prohibited and should never be treated as lawful, something the mushrikin used to do when they ate carrion or animals slaughtered in a name other than that of Allah. Also implied is the warning that it is an error to declare any animal, other than those specified, as unlawful.