Does the steadfastness of the innovator and his diligent observance of all prayers in congregation indicate the soundness of his deeds and beliefs, and what is his standing with Allah?

Every innovation (bid'ah) must be rejected and denounced, and there should be no leniency in this regard, for the Prophet, peace and blessings be upon him, said: "Whoever does an action that is not in accordance with our matter (religion), it will be rejected," meaning it is null and void and not recognized. The apparent righteousness or diligence in worship of the one who commits an innovation should not affect the legal stance towards it, for their apparent piety does not necessarily entail the soundness of their belief and action. Indeed, a person may perform the deeds of the people of Paradise, but in reality, they are among the people of Hell. A man may be martyred, or acquire knowledge, or recite the Qur'an, or spend money, seeking praise rather than the Face of Allah. The Khawarij are an example of this; the Prophet, peace and blessings be upon him, described them as diligent in worship, yet they would pass through the religion like an arrow through a target. A person may fall into innovation unintentionally due to error, and we hope that Allah will forgive them. If a scholar or an Imam errs, their mistake is forgiven, but we do not follow them in their innovation, and we hope for their repentance. A believer may combine good and evil; they are praised for the good and condemned for the evil after being advised and guided.