He (Mirza Ghulam) disbelieved the fact that Isa(Alaihis-Salam) (Jesus) will descend from Heaven. He claimed that “Jesus was crucified; He was not without a father: He was the son of Yusuf-i Najjar (Joseph the Carpenter).” Like Jews, he uttered very ugly imprecations about this exalted prophet. Mirza announced that he himself was a prophet with a new Shariat and claimed that “The word, ‘Isa will descend from Heaven,’ predicted my (his) coming”. He changed (meaning of) ayat al-karimas and hadith ash-Sharifs and denied Islamic doctrines that are to be absolutely believed. He disbelieved the fact that Muhammad(Alaihis-Salam) is the very Last Prophet and superior to all others. Instead, he claims that he had thousands of miracles and that his miracles were more numerous and more significant than the miracles of all other prophets! He even claimed that many ayats had predicted his coming and that he has been praised in Qur’an al-karim!
Ahmad Qadiyani was born a Tatar, a member of the Mongol race. He was a zindiq in the Ismaili sect who read many books. He was an implacable enemy of the Ahl as-sunnat. The British had been seeking the pincers who would carry out the plans they had prepared to demolish Islam from within. They selected him and bought him out with plenty of money. First, he was made to appear as a Bahai. Mirza declared that he was a mujaddid; then, he professed to be the promised Mahdi; then, he announced that he was Isa Messiah, whose descend from the heaven was prophesied; finally, he proclaimed that he was a prophet with a new religion. Mirza wrote that his mosque in Qadiyan was Masjid al-Aqsa (really in Jerusalem), his city was Mecca, and Lahore city, where he settled afterwards, was Medina. He established a cemetery, called it Maqbara-tul-Janna, and said anyone buried there would go to Paradise. He called his own wives Ummahat-ul-Muminin (mother of the believers) and named the people he had deceived His Ummat. He said that his greatest miracle was the nikah (marriage) with (another married woman) by the name of Muhammadi Baygum. He said that marriage was performed in heaven and was revealed to him through wahy (revelation)! Mirza declared his religion in 1305  and went to Hell in 1326 . He called anyone who did not accept his claim Kafir (disbeliever).
This zindiq stated on page 148 of his book Haqiqa-tul-wahy, “In this ummat, Allah has created a Messiah superior to Isa. If Isa (Jesus) were alive now, he could not do as I do. The miracles I have been performing would not be seen on him.” On page 107, he claimed that the prophet mentioned in the ayat, “As I sent a Messenger to Pharaoh, so I send you a Messenger,” was intended for he himself. He wrote on page 68, “Allah sent me as a prophet. He said: ‘You are the promised Messiah.’ He gave me three hundred thousand miracles.” Finally, on page 56 of his book Barahim-ul-Ahmadiyya, he declared that his miracles were superior to Muhammad’s(Alaihis-Salam) miracles.
There are one hundred and fifty hadith ash-Sharifs declaring that Hadrat Muhammad is the Last Prophet. Thirty of them are written in Kutub-i sitta. Also, it is absolutely declared that Isa(Alaihis-Salam) will descend from Heaven. They are disbelievers because they disbelieve these facts. They are not Muslims.
[The address of Allama Kashmiri to his students in the Mosque of Dyobund]
“According to my thorough study of Islam, in the last fourteen hundred years, there has not been a Fetna as serious as that spread by the Qadianis. Uninformed Muslims are threatened by this dangerous and misleading fetna…
Prophet Muhammad(pbuh) will be very pleased with the person who devotes himself for the purpose of exposing and removing this fetna (which is directed toward his(pbuh) Prophethood) and will be more satisfied with this effort than with any other.”
(As Recorded by Allama Maulana Muhammad Cheragh in his book “Cherage Hedayat” and Reported by Hazrat Allama Afghani.)
Allama Anwar Shah Kashmiri wrote many books, in Arabic and Farsi, to counter the misinformation campaign by the Qadianis. These included:
Aqeeda-tul- Islam fi hayat-i Isa ‘alaihis-salam
(Islamic faith regarding the life of Jesus(pbuh))
Tahiyyat-ul-Islam fi Hayat Isa alahissalam
Al-Tasrih fi ma twatara fi Nuzulil Masih
Tafseer of Ayah Khatam-ul-Nabiyyen