Is the congregational prayer valid if the Imam sat for the Tashahhud after the third Rak'ah, thinking it was the final Tashahhud, then was alerted and completed the fourth Rak'ah, and performed a prostration of forgetfulness before the Taslim? And does the ruling differ among the jurisprudential schools, knowing that the country follows the Maliki school of thought?

If the Imam sits inadvertently in the third rak'ah, then completes his prayer and performs the prostration of forgetfulness (sujood as-sahw) before the tasleem, his prayer is valid by the agreement of the four madhhabs. This holds true even for the Malikis and Hanbalis, who prefer prostrating after the tasleem in some cases, and for the Shafi'is, who consider sujood as-sahw to be sunnah (recommended) and its place to be before the tasleem, and for the Hanafis, who believe its place is after the tasleem.