Marriage With Ahmadi
We have no authority to declare any one kafir if he or she insists that they are Muslims. It is the authority of God to declare someone kafir. the people of book is a factual position after which they are titled, though they were not holding the true teachings of the books. anyone who claims to be Muslim, no matter how erroneous his beliefs are to us, he or she will be regarded as Muslim.
Musailma and other claimants of prophethood did not make Taweel or their beliefs but added their belief on their own authority. Taweel has been accepted as excuse by God. Trinity is declared as polytheism in Quran still the Christians were not all polytheists but the people of book and Muslims are allowed to marry their women. They were called Nasaara, as they adopted this name for themselves. It is the authority of God not to accept a Taweel and declare someone or group kaafir, but still we find that God gives concession. as far as we are concerned we have no authority declare anyone kaafir. it is intrusion into the domain of God’s authority.