Ruling about the Ahmadiyyah (Qadiyani)
4-8-2004 | IslamWeb
Question:
My question is about Ahmadiyyah. I understand that they are considered Kuffaar. I know that there are two branches: Qadiyani and Lahori. The Lahori sect doesn't claim that there Ahmed is a prophet. They consider him as you know as "Mujaddid". I really don't believe that, but is that alone considered a reason to call a person as a Kaffir. My classmate is an Ahmadi and I know that this group is very outspoken. As an average Muslim, I really want to know if that belief is sufficient for making that person a Kaaffir.
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad 
is His slave and Messenger.
Qaadyani is a destructive disbelieving group that names itself Muslim to mask its obnoxious filthy objectives and beliefs. The most dangerous of their beliefs are their claim that their leader is a Prophet, they alter the Quran, they believe that there is no Jihaad, they declare Muslims as non-Muslims and they are allies to the non-Muslims.
The Qaadyani liar (prophet) followed a step-by-step progression in his propaganda using means similar to those used by the secret sects and the Ismaa'eelees.
Firstly, he claimed that revelation came down to him through inspiration. Secondly, he claimed that he was the reformer of his era and that he was similar to Prophet 'Eesaa Ibn Maryam 
in his modesty, his peacefulness and his gentleness.
In the third phase of his fallacy, he claimed that he was the Messiah who is to descend in the last times. But at first he said that he was only partly a Prophet. Then he claimed full Prophecy. Finally, he claimed to have become Krishna which is the name the Hindus give to their 'God'. They believe in him in the same manner the Muslims believe in Allaah. After this liar died, he was succeeded by Noor Ad-Deen. Then after his death the Qaadyani's split into two groups. A group led by Mirza Bashir Ad-Deen Mahmood and called Ahmadiyyah. A second group was led by Mohammed Al-Lahori and called Al Lahori or Al Ahmadi.
Both groups follow the liar (prophet), follow his sayings and consider his books as sacred. However, the first group declares solely that he is a Prophet. While the second group (Lahori) believes he is the awaited Messiah and the reformer of the fourteenth Hijrah century. But this is just something he conspired with some of his followers and an attempt to deceive people to get more followers.
So, both groups glorify and follow every word that the liar says. This is why the Muslim scholars do not differentiate between them. Disbelief is but one path, even though its kinds and ways are numerous.
There is a consensus of the Muslim nation that the Qaadyan's followers are disbelievers, outside the fold of Islam. The regional council of the department of the northern frontiers in Pakistan passed a decision considering the Qaadyanis a non-Muslim minority.
Moreover, the Islamic Fiqh Committee which is affiliated with the World Islamic Conference passed a decision with the consensus of all its members, considering the Qaadyani creed completely non-Islamic and considering its followers as complete renegade apostates who left Islam. The Committee declared that all Muslims, governments, scholars, writers, intellectuals and Callers to Islam should confront this devious sect and its followers everywhere in the world.
So, dear brother, you should desert that colleague until he repents, and beware of befriending him. Allaah says (what means): {You will not find a people who believe in Allaah and the Last Day having affection for those who oppose Allaah and His Messenger, even if they were their fathers or their sons or their brothers or their kindred. Those — He has decreed within their hearts faith and supported them with spirit from Him. And We will admit them to gardens beneath which rivers flow, wherein they abide eternally. Allaah is pleased with them, and they are pleased with Him — those are the party of Allaah. Unquestionably, the party of Allaah — they are the successful..}[Quran 58:22].
Besides, Al-Baraa' Ibn 'Aazib 
narrated that the Prophet said: "The strongest knot of the Islamic creed is the love for the Sake of Allaah, the hatred for the Sake of Allaah, the amity for the Sake of Allaah, and the enmity for the Sake of Allaah." [Ahmad]
Allaah Knows best.