Does one who commits an act of disbelief or innovation become a disbeliever or an innovator?

Question:
The questioner asks: Is it permissible for a Muslim to declare someone a disbeliever or an innovator for every person who commits an act of disbelief or innovation?

Answer:
Rushing to judge people, declaring them disbelievers, or labeling them as innovators is not permissible except for the people of knowledge who know the boundaries of disbelief, the boundaries of innovation, and the boundaries of apostasy, and who know the causes that the people of knowledge recognize. This is the exclusive domain of the people of knowledge. It is not permissible for anyone to judge another as an innovator, a disbeliever, or one who associates partners with Allah if he does not know or understand the conditions for declaring someone a disbeliever, the conditions for labeling someone an innovator, and the conditions for labeling someone an open sinner. A person should guard his tongue, for he may say to an innocent person that he is a disbeliever, an innovator, misguided, or an open sinner. The Prophet (peace and blessings be upon him) said: "O open sinner," when he was not such, and his words will return to him.
His words will return to him, may Allah protect us. Therefore, a person must guard his tongue and not let it run loose in these matters. This is serious and requires that a person learns and understands the conditions for declaring someone a disbeliever, the conditions for labeling someone an innovator, and the conditions for labeling someone an open sinner. He should not speak out of ignorance, emotion, enthusiasm, or anything else. He may fall into error, and his words will return to him. The matter is very serious. This speech regarding declaring people disbelievers, labeling them innovators, or labeling them open sinners does not go to waste. If they are deserving of it, it reaches them; if they are not deserving, it returns to you. You must guard your tongue in these matters.