What is the ruling on one who forgot that he was in a state of major ritual impurity and prayed until he completed the prayer?

The Shaykh : But I thought you would mention that the issue differs—there is a precision in the matter here—it differs if one remembers the major ritual impurity after the prayer has ended, meaning he completed the entire prayer while not in a state of ritual purity! In this case, he must perform the full ritual bath and repeat the prayer. Our evidence for this is the story of 'Umar ibn al-Khattab in Sahih al-Bukhari. And were it not for that, we would have included this second scenario with the first. "Umar ibn al-Khattab led the people in the Fajr prayer one day, then noticed that he was in his state of major ritual impurity. He went and performed the full ritual bath and repeated the prayer, but he did not order the people to repeat the prayer."
The student : So, there is a difference between a part and the whole.

The Shaykh : Yes, so we follow the Prophetic text in its reality entirely, and we follow the report of 'Umar in its reality entirely, and there is no contradiction between them.

The questioner : Shaykh, is your opinion that it is based on what has passed?

The Shaykh : Yes, exactly.

The questioner : Well, once we prayed together, you and I, and I saw you repeat the prayer.

The Shaykh : We prayed in a place, under certain circumstances.

The questioner : I want to ask about the circumstances.

The Shaykh : Yes.

The questioner : We prayed at Jamil's place. When I was reaching the tashahhud, you signaled to me and you withdrew.

The Shaykh : Yes, because where would I go to perform the ablution, and where would I renew it?

The questioner : Meaning you went and performed the ablution.

The Shaykh : Many actions.

The questioner : I performed the ablution and prayed, and I started from the beginning, from the start.

The Shaykh : Yes, because I turned away from the qiblah and did major actions.

The questioner : What if it was in the same direction as the qiblah?
Al-Halabi : So this is another point to be considered, Professor?

The Shaykh: Yes.
Al-Halabi : Another important point. May Allah reward you with good.

The questioner : In the final tashahhud...
Al-Halabi : Leave us from this image, meaning, for now, a new image.

The Shaykh: Yes.
Al-Halabi : One who, in the middle of his prayer, remembers, and the ablution area is near him on the right, for example, he performs the ablution quickly and then returns; there is nothing wrong with this.

The Shaykh: Yes.
Al-Halabi : But he has to go up stairs and down stairs, and go and come, and so on.

The Shaykh : Meaning, there are many actions that contradict the prayer.

The questioner : Yes, the violations of the form of the prayer are many.

The Shaykh : It is this.