Ruling on one who catches the imam in the final tashahhud, sits down, and does not say takbir

The question: From the city of al-Nazilah in Matrouh Governorate, Arab Republic of Egypt. The listener: Muhammad Jibril al-Mallah asks and says:
If I enter the mosque and find the worshippers in the final tashahhud, and I sit with them until the taslim, am I then required to go back to establish the prayer, knowing that I did not say the takbir of ihram? May Allah reward you with good.
The answer: If you did not say takbir and sat down without takbir, then you have no prayer, and you must say takbir when you begin the prayer. However, the best for you, if you come and they are in the final tashahhud, is that you should say the takbir of ihram while standing, then sit with them and recite the tashahhud. Following the imam is better. Then, when the imam says taslim, you stand and complete your prayer. This is based on the saying of the Prophet (peace and blessings be upon him): , and in the other wording: . So the Sunnah for one who comes while the imam is sitting in the final tashahhud is to join him in the prayer, say the takbir of ihram while standing, and then sit. If he says takbir when sitting, there is no harm in that. He recites the tashahhud, and when the imam says taslim, he stands and prays the rest of his prayer. Yes.
The presenter: May Allah reward you with good.