And I shall not worship that which you are worshipping.
Nor will you worship whom I worship.
meaning, `I do not worship according to your worship, which means that I do not go along with it or follow it. I only worship Allah in the manner in which He loves and is pleased with.'
Thus, Allah says,
وَلَا أَنتُمْ عَـبِدُونَ مَأ أَعْبُدُ
(Nor will you worship whom I worship.)
meaning, `you do not follow the commands of Allah and His Legislation in His worship. Rather, you have invented something out of the promptings of your own souls.'
This is as Allah says,
إِن يَتَّبِعُونَ إِلاَّ الظَّنَّ وَمَا تَهْوَى الاٌّنفُسُ وَلَقَدْ جَأءَهُم مِّن رَّبِّهِمُ الْهُدَى
They follow but a guess and that which they themselves desire, whereas there has surely come to them the guidance from their Lord! (53;23)
Therefore, the disavowal is from all of what they are involved. For certainly the worshipper must have a god whom he worships and set acts of worship that he follows to get to him. So the Messenger and his followers worship Allah according to what He has legislated. This is why the statement of Islam is
"There is no God worthy of being worshipped except Allah, and Muhammad is the Messenger of Allah."
This means that there is no (true) object of worship except Allah and there is no path to Him (i.e., way of worshipping Him) other than that which the Messenger came with.
The idolators worship other than Allah, with acts of worship that Allah has not allowed. This is why the Messenger said to them,
لَكُمْ دِينُكُمْ وَلِيَ دِينِ