In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Allaah [The Exalted] said:
وَقَالَ ٱلَّذِينَ أَشۡرَكُواْ لَوۡ شَآءَ ٱللَّهُ مَا عَبَدۡنَا مِن دُونِهِۦ مِن شَىۡءٍ۬ نَّحۡنُ وَلَآ ءَابَآؤُنَا وَلَا حَرَّمۡنَا مِن دُونِهِۦ مِن شَىۡءٍ۬ۚ كَذَٲلِكَ فَعَلَ ٱلَّذِينَ مِن قَبۡلِهِمۡۚ فَهَلۡ عَلَى ٱلرُّسُلِ إِلَّا ٱلۡبَلَـٰغُ ٱلۡمُبِينُ
And those associate others in worship with Allah say: “If Allah had so willed, neither we nor our fathers would have worshipped aught but Him, nor would we have forbidden anything without (Command from) Him.” So did those before them. Then! Are the Messengers charged with anything but to convey clearly the Message? [Surah An-Nahl. Aayah 35]
The polytheists used as proof that had Allaah [The Exalted] willed, then neither would they have ascribed partners to Him in worship nor would they have declared forbidden the Baheerah [a she-camel whose milk was spared for the idols and nobody was allowed to milk it] or a Saa’ibah [a she-camel let loose for free pasture for their false gods and nothing was allowed to be carried on it], or a Ham [a stallion-camel freed from work for their idols, after it had finished a number of copulations assigned for it] and their like. This is a false proof, because if it was truth Allaah would not have punished those who came before them when they ascribed partners to Him. If Allaah wished that they should ascribe partners to Him in worship, then He would not have punished them; rather the intention behind this [claim] of theirs is nothing but to reject the truth brought by the Messengers and they know that they have no proof against Allaah regarding this. They have knowledge regarding the fact that Allaah gave them commands, prohibitions and the ability to fulfil what has been obligated on them, and their deeds emanates from the strength and free will they have been given. Therefore, using Allaah’s Divine Will and Decree to commit sins is the falsest falsehood. Everyone knows the ability of a human being to do what he wants without another person disputing with him about this; but the polytheists combined between wilfully disbelieving in Allaah and His Messengers, and denied the affairs that are known by way of sound intellect and are based on tangible reality.
[فَهَلۡ عَلَى ٱلرُّسُلِ إِلَّا ٱلۡبَلَـٰغُ ٱلۡمُبِينُ – Then! Are the Messengers charged with anything but to convey clearly the Message?] – Meaning, that which is manifestly clear and reaches the hearts, so there remains no proof for anyone against Allaah. Therefore, after the Messengers conveyed to them the commands and prohibitions of their Lord and they utilised Divine Will and Decree [to turn away], then the Messengers do not have any control over the affair; rather Allaah is the one who will finally call them to account on the day of judgement.
[An Excerpt from Tafseer as-Sadi. Slightly paraphrased]