While I was reciting the final tashahhud, I remembered that I had forgotten the second prostration, so I continued reciting the tashahhud and then performed the prostration for forgetfulness?

Question:
May Allah reward you with good and do you good. One of the listeners says: I prayed the midday prayer, and at the end of the fourth rak'ah I prostrated once, then I recited the final tashahhud. While I was reciting the tashahhud, at the beginning of it, I remembered that I had forgotten the second prostration and the sitting between the two prostrations. However, I continued reciting the tashahhud until the end, then I performed the prostration for forgetfulness before the taslim, and then I said the taslim. Is my action correct or incorrect? And what is obligatory for me to do? May Allah reward you with good.

Answer:
This action is not correct; because you left out two pillars of the prayer, which are the second prostration and the sitting between the two prostrations. These are two pillars of the prayer, and the prayer is not valid without them. So you must repeat this prayer from which you left out these two pillars. If you had remembered soon, and then you had performed the second prostration, meaning you had performed the sitting between the two prostrations, then prostrated the second prostration, then performed the final tashahhud, then said the taslim, and then prostrated two prostrations for forgetfulness, that would have been correct. But since the interval was long, and time had passed, you must repeat the prayer in its entirety.