Shaykh-ul-Islām Ibn Taymiyyah said,
And they (the imams of the deen) all agree that no one is infallible (and free from error) in that which they command and forbid except the Messenger of Allah ﷺ. Due to this, more than one of the imams (of Islaam) have said, “Everyone’s statement could be accepted and rejected except for the Messenger of Allah ﷺ.”
The Four Imams (may Allah mercy upon them) prevented people from blind following them. This is what was binding upon them.
Imam Abu Haneefah said,
This is just my opinion. If someone comes with a better opinion, accept it from him.
Imam Maalik used to say,
Verily I’m not but a human being, I am correct (at times) and I am wrong (at times). Therefore, compare my statements to the Book and the Sunnah (and abandon them if they contradict the Book and the Sunnah).
Imam Ash-Shaafi’ee said,
If the Hadeeth is authentic, throw my statement against the wall.
Imam Aḥmad said,
Don’t blindly follow me; don’t blindly follow Maalik, Shaafi’ee or Thawree. Seek knowledge (and learn for yourself) as we have sought (and learned for ourselves).