Is a person sinful if they commit an innovation (bid‘ah), or does the reward for their deed fall away and they receive nothing from it?

A Muslim is not permitted to commit innovation (bid'ah). If he commits it while knowing it is an innovation, he is sinful, because the Prophet, peace and blessings be upon him, said: "Beware of newly invented matters, for every newly invented matter is an innovation (bid'ah)." And his saying: "Whoever performs an action which is not in accordance with our matter, it will be rejected," meaning it is null and void, not recognized. So, whoever commits it while knowing it, will receive neither reward nor recompense, and his action is contrary to the Sacred Law. And whoever intentionally violates the Sacred Law is sinful.