Does the prayer of the follower become invalid if the imam errs in his sermon? And what is the ruling on attending the sermon in a mosque of this nature?

The Shaykh : As for whether the prayer becomes invalid because of that? The answer is: No. First, it has no bearing on the ruling regarding the prayer. Second, the one who errs, who is this preacher who urges people to do actions, is not the one who must listen and remain silent; rather, it is obligatory for them to listen and be silent. So if the preacher makes a mistake, what does that have to do with the one praying? We look at his prayer. If his prayer is valid, then the prayer is valid. Otherwise, the schools of jurisprudence differ here. Some say that the prayer of the follower becomes invalid if the prayer of the imam is invalid, so the prayer of the follower is invalid. And some, like us, say that the prayer of the follower is valid, and the sin of the invalidity of the imam's prayer is upon himself, whether he did it intentionally or by mistake. Because the Messenger (peace and blessings be upon him) said: .
The last part of the question asks: What is the ruling on attending the sermon in a mosque of this nature? We say: Without a doubt, if there is a mosque that does not have such a major sin, and it is easy for the Muslim to go to that mosque, then that is obligatory. It is established from Ibn 'Umar (may Allah be pleased with him) that he entered a mosque one day and heard a man calling out after the adhan, as they do in some mosques to this day: "Prayer, prayer, O you who pray, prayer." So he said to his companion: "Let us go out, for this is a mosque in which there is religious innovation." If Ibn 'Umar had seen our mosques today, he would not have prayed in any of them at all.
But is this correct? The answer is: It is not correct. It is only correct to choose the mosque that has less religious innovation than the others. As for seeking out a mosque that has no religious innovation, and whose imam is upon the Sunnah, and whose prayer and sermon are correct; that is seeking something that does not exist, unfortunately.
We have finished with the question.