Overall meaning : The Almighty instructs to His Prophet, Muhammad, may Allah bless him and grant him peace, to say to these idolaters: Am I to stray from the truth and seek a judge other than Allah when it is He who has sent down the Qur’an to you containing judgements on your disputes and explaining all beliefs and rulings? He then affirms that the Jews and Christians to whom He has previously given the Torah and the Gospel know full well that this Qur’an is the truth revealed by Him, and instructs His Prophet, may Allah bless him and grant him peace, not to doubt any aspect of it.
Perfected are His words in truth and justice, He proclaims. Whatever He says is the truth and whatever ruling or legislation He pronounces is just. None can change His words, and He is the All-Hearing, the All-Knowing.
Then, directing His speech to his Prophet Muhammad, may Allah bless him and grant him peace, He declares that if he obeyed most people on earth, they would mislead him and turn him away from His religion, stating that they adhere to false assumptions and follow nothing but conjecture, and that they invent lies about Allah and say about Him what they do not know.
Next, He asserts that He is best aware of those who stray from the right path, as He best knows those who are rightly guided.