Ruling on the prayer of one who said the closing salam before completing the final tashahhud

Q: It is well known that the final tashahhud is a pillar of the prayer. In one of the prayers, the imam said the closing salam, and I had only completed a small part of the tashahhud. Do I have to repeat my prayer?

A: You must complete the tashahhud, even if you are slightly delayed behind your imam; because the final tashahhud is a pillar in the most correct opinion of the scholars, and it includes the prayer upon the Prophet (peace and blessings be upon him).
Therefore, it is obligatory for you to complete it, even after the imam has said the closing salam. This includes seeking refuge in Allah from the punishment of the Hellfire, from the punishment of the grave, from the trial of life and death, and from the trial of the Dajjal (the false messiah); because the Prophet (peace and blessings be upon him) commanded seeking refuge from these four in the final tashahhud, and because some scholars have held that it is obligatory. And success is from Allah.