What is the criterion for bid'ah (religious innovation) and shirk (associating partners with Allah)?

Question:
The questioner asks: What is the criterion for declaring someone an innovator or an associate of partners with Allah, and does one who commits shirk become a mushrik (one who associates partners with Allah)?

Answer:
Yes, one who commits major shirk becomes a mushrik, and he must repent to Allah (Glorified and Exalted is He).
Declaring someone an innovator means that he has committed a bid'ah. One who commits a bid'ah, and bid'ah is what is attributed to the religion without any evidence from the Shari'ah. It is what is attributed to the religion without any evidence from the Shari'ah. The saying of the Messenger (peace and blessings be upon him): "Whoever does a deed..." in one narration .
This is bid'ah; this is the criterion for bid'ah as stated in the hadith. However, in our present time, people have started speaking about declaring others innovators, saying "so-and-so is an innovator" and "so-and-so is such-and-such," without any criteria. They say anyone who disagrees with them is an innovator. It is necessary that bid'ah be a contradiction of the Book of Allah and the Sunnah of His Messenger (peace and blessings be upon him).
Not everyone knows what bid'ah is; not everyone knows what bid'ah is. Bid'ah is known only by the people of knowledge who know the Sunnah and bid'ah. Therefore, it is not permissible to be excessive in this matter except after verification, after verification. Perhaps a person did something contradictory out of ignorance, so do not rush to declare him an innovator until it is clarified to him. Perhaps he did not know, and if it is clarified to him, he will abandon this contradiction. Yes, matters require criteria in declaring someone an innovator, declaring someone a disbeliever, and judging people. There must be Shari'ah criteria. Yes, and it must be based on knowledge. Yes.