Saying of Scholars of Ahlus-Sunnah in the Past and Present about the Syiah Rafidah ?
1) Imam Ash-Shafie: On one occasion Imam Shafie said concerning the Shia,
"I have not seen among the heretics a people more famous for falsehood than the Raafidi Shia", and on another occasion he said; "Narrate knowledge from everyone you meet except for the rafidi Shia, because they invent hadith and adopt them as part of their religion." - Minhaj as-Sunnah an-Nabawiyyah
Some shia at the time of the Alid Imam Zayd ibn Ali demanded that he make a declaration of innocence ( tabarra ) from whoever disagreed with Ali's right to be Imam. When Zayd refused, they rejected him, and became known as the "raafida" or rejectors. Those who followed Imam Zayd became known as Zaydis, and have very little difference from mainstream Islam. The Raafidi evolved into the the various Imami shia sects, the largest of which is the Ithna 'Ashari.
2) Imam Abu Hanifah: It is reported that often Imam Abu Hanifah used to repeat the following statement about the raafidi Shia; "Whoever doubts whether they are disbelievers has himself committed disbelief."
3) Imam Malik: Once when asked about the raafidi Shia, Imam Malik said; "Do not speak to them or narrate from them, for surely they are liars." During one of Imam Malik's classes, it was mentioned that the raafidi Shia curse the sahabat. Imam Malik recited the verse, "Muhammad is the Messenger of Allah and those with him are harsh with the disbelievers and gentle among themselves. So that the disbelievers may become enraged with them." (48:29) He then said, "Whoever becomes enraged when the sahaba are mentioned is the one about whom the verse speaks." -Tafseer al-Qurtubi
4) Abu Zur'ah ar-Razi: He said of the raafidi Shia doctrine of cursing the sahaba, "If you see someone degrade any of the companions of the ProphetSAWS know that he is a disbeliever. Because the Prophet s.a.w was real, what he brought was the truth and all of it was conveyed to us by way of the sahabat. What those disbelievers wish to do is cast doubt on the reliability of our narrators in order to invalidate the Qur'an and Sunnah. Thus the disbelievers are the ones most deserving of defamation."
5) Ibn Hazm al-Andalusi: During the period of Muslim rule in Spain, Imam Abu Muhammad ibn Hazm would often debate with the Catholic priests about their religious texts. He brought before them evidence of textual distortions in the Bible and the loss of the original manuscripts. When they replied by pointing out the Shia claims that the Qur'an has been distorted and altered, Ibn Hazm informed them that Shia claims were not valid evidence because the shia were not themselves muslims.
6) Imam Al-Alusi: He declared the raafidi Shia disbelievers because of their defamation of the sahabat ( Prophet Muhammad's companions). His position was based on the rulings of Imam Malik and other scholars. In response to their claim to be followers of the Ahlul Bait (the Prophet's s.a.w family) Al-Alusi said, "No, they are really followers of the devils and the Ahlul Bait are innocent of them."
7) Muhammad Rasheed Rida: This scholar was among those who worked sincerely for rapproachment between the shia and the sunni, and they in turn pretended moderation for his benefit. However, in the midst of his efforts, they caught him by surprise by presenting him with a number of their books which slander Islam. He then replied in a paper called As-Sunnah wa Ash-Shia in which he exposed their false doctrines and idolatrous practices.
8) Dr. Hilali: After living close to the shia for some years, the famous Moroccan scholar, Dr. Hilali wrote a paper on them in which he declared them to be disbelievers.
9) Abul-A'la Maududi: This great Pakistani scholar wrote an introduction to the book, "Ar-Riddah bain al-Ams wa al-Yaum" In it was written, regarding the Imami Ja'fari Shia, "despite their moderate views (relative to other shia sects), they are swimming in disbelief like white bloodcells in blood or like fish in water."
10) Imam Bukhari declared: “I don’t see any difference between praying Salah behind a Jahmi or a (Shia) Rafidhi and a Christian or a Jew. They (Jahmis/Rafidhis) are not to be greeted, nor are they to be visited, nor are they to be married, nor is their testimony to be accepted, nor are their sacrifices to be eaten.” -Khalq Af’aalul-’Ibaad, p.14
11) among the other contemporary scholars who have expressed similar views are: Sheikh Abdul 'Aziz ibn Baz, Sheikh Nassiraddin Al-Albani, Allama Ash-Shanqiti, Sheikh An-Nashashibi, Imam Ahmad Ameen, and Dr. Rashaad Salim.
(edited from islamicemirate)