6:106

اتَّبِعْ مَا أُوحِيَ إِلَيْكَ مِن رَّبِّكَ ۖ لَا إِلَٰهَ إِلَّا هُوَ ۖ وَأَعْرِضْ عَنِ الْمُشْرِكِينَ

Follow, what has been revealed to you from your RABB – there is no deity except Him – and turn away from those who associate others with Allah.

Bangla

আপনি পথ অনুসরণ করুন, যার আদেশ পালনকর্তার পক্ষ থেকে আসে। তিনি ব্যতীত কোন উপাস্য নেই এবং মুশরিকদের তরফ থেকে মুখ ফিরিয়ে নিন।

Critical Reasoning: Extracting UNKNOWN from Known:

Allah didn’t use the word Kuffar or Kafir but Mushrikeen but you said Kuffar and Mushrikeen, why?

By the theory, ‘Not all Mushrikeen are Kuffar but all Kuffar are Mushrikeen’

How all Kuffar could be Mushrikeen?

Allah sent the last messenger Muhammad Salla Allahu alaihi wa sallam only when the world was submerged in SHIRK. There were many at that time who believed in Allah but they also believed in other things with Allah, they worship other things along with Allah Subhanahu such as Quraish pagans, Jews, the Roman Christians, the Persian Zoroastrian pagans, the Hindu Mushrikeen, the Egyptian pagans. They were Mushrikeen before the advent of Rasulullah

And then they became Kuffar by rejecting the Messenger, Muhammad Salla Allahu alaihi wa sallam and by rejecting the Quran that he sent with.

Therefore, all Kuffar are actually Mushrikeen.

What about the atheists Kuffar?

They are Mushrikeen too. Not only they reject to believe in Allah Taa’la and became Kafir but they also worship their NAFS, their desire and that’s how they became Mushrikun too.

By the way, in today’s context, this Ayah also applies to the Mushrikeen among ‘Muslims’.

How come, even though they utter ‘La Ilaha Illa Allah’?

Yes, even though they say ‘La Ilaha Illa Allah’ by their lips but they live with many other Ilaha along with Allah as the Kuffar do.

And Allah knows best.

May Allah guide the Muslims.

Ameen.