In ‘Al Ibānah Al Kubrā’ (104) 📚 Imām Ahmad may Allah have mercy on him, said:
“I looked into the Mushaf and found in it obedience of the Messenger of Allah, peace and blessings be upon him, in 33 places,” then he started reciting: {فَلْيَحْذَرِ ٱلَّذِينَ يُخَالِفُونَ عَنْ أَمْرِهِۦٓ أَن تُصِيبَهُمْ فِتْنَةٌ أَوْ يُصِيبَهُمْ عَذَابٌ أَلِيمٌ} [An-Nūr], and he began to repeat it, and say: “And what is the fitnah? Shirk, perhaps something of deviance will settle in their heart so it will deviate their heart and destroy them.”And he began to recite this verse: {فَلَا وَرَبِّكَ لَا يُؤْمِنُونَ حَتَّىٰ يُحَكِّمُوكَ فِيمَا شَجَرَ بَيْنَهُمْ ثُمَّ لَا يَجِدُواْ فِىٓ أَنفُسِهِمْ حَرَجًا مِّمَّا قَضَيْتَ وَيُسَلِّمُواْ تَسْلِيمًا} [An-Nisā: 65].
And he said: whoever rejects a Hadīth of the Prophet peace and blessings be upon him, then he is on the verge of destruction.”