In congregational prayer, if I arrive late while the imam is saying the taslim, should I say the tashahhud up to "I bear witness that there is no god but Allah and that Muhammad is His slave and Messenger" and then stand to complete my prayer, or should I say it in full? And if I prayed without knowing the ruling, am I obliged to repeat that prayer? And why does the imam shorten the interval between his recitation of Al-Fatiha and the other verses, and should we recite Al-Fatiha silently or only listen to the Qur’an in congregational prayer? And when joining an ongoing congregation, what should I recite in the rak'ahs I catch up with and what should I recite in the missed rak'ahs, and is the tashahhud only up to "I bear witness that there is no god but Allah"?

Fatwas have previously been issued regarding what the latecomer (masbuq) should say in the final tashahhud, under fatwa number: 39991.

If the worshipper limits himself to the tashahhud without the Salatul-Ibrahimiya, his prayer is valid and he is not required to repeat it. However, he must remain seated with the imam until the imam says the taslim. If he stands up before the imam's taslim, his prayer becomes void because he intentionally abandoned the obligation of following the imam.

The imam is not required to be silent after Al-Fatihah for the congregants to recite. See fatwa number: 41453.

As for the congregant reciting behind the imam, this is a matter of scholarly disagreement. See fatwa number: 1740.

What the latecomer (masbuq) catches with the imam is considered the beginning of his prayer, and he completes the prayer as an individual. So, if he catches two rak'ahs, he completes the rest with only Al-Fatihah, because these are the third and fourth for him. See fatwa number: 32907.

As for the tashahhud in the last rak'ah, it should be recited in full, including the Salatul-Ibrahimiya. See its wording in fatwa number: 32369.

To know the description of the prayer from the takbir to the taslim, see fatwa number: 32821.