had taken a path with the Messenger! Woe to me! If only I had not taken so-and-so as a close friend! He led me away from the Reminder after it had come to me.’ And Satan ever forsakes man.”
[al-Furqān: 27–29]

And as He says:

“On the Day their faces are turned about in the Fire, they will say, ‘If only we had obeyed Allah and obeyed the Messenger!’ And they will say, ‘Our Lord, we obeyed our leaders and our great men, and they led us astray from the path. Our Lord, give them double the punishment and curse them with a mighty curse.’”
[al-Ahzāb: 66–68]

These texts apply in some measure to everyone who follows a leader in anything contrary to the Book and the Sunnah, whether they are leaders in speculative inquiry, speculative theology, rational thought, and philosophy; leaders in jurisprudence and the discussion of religious rulings; leaders in worship, asceticism, devotion, and Sufism; or leaders in kingship, government, rule, administration, and the judiciary.

You will find none of these people free of inconsistency. Elsewhere, he himself contradicts the statements of the very leader he has exalted, since he cannot put his worldly and religious affairs in order by following that leader, whose instructions contradict one another.

By contrast, what comes from Allah is consistent and harmonious, and sets His servants’ affairs right in this life and the Hereafter.

Allah Most High says:

“If it had been from anyone other than Allah, they would have found within it much contradiction.”
[al-Nisā’: 82]

These points are discussed at length elsewhere.