Imām Al-Dhahabī (d. 748H, rahimahullāh) said that Abu al-Walīd al-Bājī said in the book Ikhtisār Firaq al-Fuqahā’ when discussing al-Qādī Abu Bakr al-Bāqillānī (d. 403H):
“I asked Abu Dharr al-Harawī (d. 434H)―and he was inclined to the Ashʿarī creed, ‘From where did you get this belief?’ He replied, ‘I was walking with Abu al-Hasan al-Dāruqutnī (d. 385H) in Baghdād and we met Abu Bakr ibn al-Tayyib [al-Bāqillānī], the Ashʿarī. So, al-Dāruqutnī embraced him, kissed his face and eyes. When they parted company, I asked him, ‘What is this that you have done? I cannot believe that you would have done such a thing―and you are the scholar of the era?!’ Al-Dāruqutnī responded, ‘He is the imām of the Muslims, a defender of the Religion, al-Qādī Abu Bakr Muḥammad ibn al-Tayyib.’ So from that moment onwards, I continued to visit him (Abu Bakr al-Bāqillānī), and started following his creed.’“
Imām al-Dhahabī said, “Abu Dharr took al-Kalām and the creed of Abu al-Hasan [al-Ashʿarī] from Abu Bakr ibn al-Tayyib [al-Bāqillānī] and spread it in Makkah, then the Maghrabīs took it from him and carried it into Maghrib (North West Africa) and Spain. Before this, the scholars of Maghrib did not used to engage in al-Kalām (speculative theology), rather they would seek precision in matters of Fiqh, Ḥadīth and Arabic―and they would not engage in futile discussions based upon the intellect. And this was the way of Abu al-Walīd ibn al-Faradī, Abu ʿUmar al-Talmankī, Makkī al-Qīsī, Abu ʿAmr al-Dānī, Abu ʿUmar ibn ʿAbd al-Barr and the [other] scholars.”
(See: Tadhkirah al-Huffāẓ 3/1104-1105, al-Siyar 17/558-559)
Look at how Imām al-Dāruqutnī’s conduct with al-Bāqillānī (the Ashʿarī) in his praise of him was enough to deceive those watching him. He extolled him and called him an imām of the Muslims, such that Abu Dharr al-Harawī adopted the madh´hab of the Ashāʿirah, and then it reached the Maghrib and Spain!
And this is the case with anyone who praises ahl al-bidʿah and al-ahwā (the people of innovation and desires)―he may become the reason for large numbers of people following their beliefs and methodologies. And this is especially so if the one praising them is seen to be a person of knowledge and upon the correct path.
(See, al-Ajwibah al-Mufīdah ʿan As’ilah al-Manāhij al-Jadīdah, FN, p. 32)
Abu Qilābah (d. 104H) said: “Do not sit with the People of Desires, for indeed I fear they will immerse you in their misguidance, or they will deceive you concerning some of what you know [to be the truth].” (Al-Ibānah ʿan Sharīʿah al-Firqah an-Nājiyah wa Mujānabah al-Firaq al-Madhmūmah of Ibn Battah, no. 369)
Mubash´shir ibn Ismā‛īl al-Hubulī said: “It was said to al-Awzā’ī (d. 157H): ‘A man says: I sit with Ahl al-Sunnah and with Ahl al-Bidʿah.’ Al-Awzāʿī responded: ‘This man wants to unite truth and falsehood.’” So, Ibn Battah (d. 387) said: “Al-Awzāʿī has spoken the truth. I say: This man does not know truth from falsehood, nor kufr from īmān. It was for the likes of this person that the Qur’ān was revealed, and the Sunnah was reported from the chosen Prophet (صلى الله عليه وسلم). Allāh said:
وَإِذَا لَقُوا الَّذِينَ آمَنُوا قَالُوا آمَنَّا وَإِذَا خَلَوْا إِلَىٰ شَيَاطِينِهِمْ قَالُوا إِنَّا مَعَكُمْ
“And when they meet those who believe, they say: We believe; but when they are alone with their evil ones, they say, Indeed, we are with you.” (Ibid, no. 435)