And his statement (may Allah bless him and grant him peace): "For every forgetfulness, there are two prostrations after the salutation." Narrated by Abu Dawud (16). This is because it is a forgetfulness, so one prostrates (17) for it as he does for other instances of it, along with what we will mention in the detailed issues.
As for standing in the place of sitting, it involves three scenarios: The first is that he omits the first tashahhud and stands up, and this involves three issues: The first: remembering before he is fully standing, in which case he is obligated to return to the tashahhud. Among those who said he should sit are Alqamah, al-Dahhak, Qatadah, al-Awza'i, al-Shafi'i, and Ibn al-Mundhir. Malik said: If his buttocks have left the ground, he continues. Hassan ibn ‘Atiyyah (18) said: If his knees have lifted from the ground, he continues. Our evidence is what al-Mughirah ibn Shu'bah narrated from the Prophet (may Allah bless him and grant him peace), who said: "If one of you stands up in the two rak'ahs and has not fully stood, let him sit down. But if he has fully stood, let him not sit down, and let him perform the two prostrations of forgetfulness." Narrated by Abu Dawud and Ibn Majah (19). Also because he has failed to perform a wajib (obligation) while remembering it before engaging in a core pillar of the prayer, so he is obligated to perform it, just as if his buttocks had not left the ground.
The second issue: remembering after he has fully stood and before engaging in recitation. It is better for him not to sit, but if he does sit, it is permissible. This is textually stated by him (20). Al-Nakha'i said: He should return as long as he has not begun the recitation. Hammad ibn Abi Sulayman said: If he remembers the moment he stands, he should sit. Our evidence is the hadith of al-Mughirah and what we will mention later, and because he remembered it after engaging in a pillar, so he is not obligated to return, just as if he had remembered it after beginning the recitation. It is possible [that it is not permissible] (21)
(16) Preceded on page 388. (17) In MS (m): "fa-sajada" (he prostrated). (18) Abu Bakr Hassan ibn ‘Atiyyah al-Muharibi, their freedman, the Damascene. He was trustworthy and pious. Al-Bukhari mentioned him among those who died between the years 120 and 130 AH. Tahdhib al-Tahdhib 1/251. (19) Recorded by Abu Dawud in: Chapter of One Who Forgets to Perform Tashahhud While Sitting, from the Book of Prayer. Sunan Abi Dawud 1/238. And by Ibn Majah in: Chapter of What Has Been Said Regarding One Who Stands Up From Two Rak'ahs Out of Forgetfulness, from the Book of Establishing Prayer. Sunan Ibn Majah 1/281. It was also recorded by Imam Ahmad in: al-Musnad 4/253, 254. (20) Meaning: Ahmad. (21) In MS (m): "that it is not permissible for him."
