Musannaf Ibn Abi Shaybah

Hasan says that if a person forgets to recite the Tashahhud and exits the prayer, then his prayer is complete, and if he has not exited the prayer, then he should recite the Tashahhud. According to Hasan, exiting the prayer means that a person speaks, or starts another prayer, or turns his face away from the Qiblah.

Hazrat Ata says that if a person forgets to recite Tashahhud in prayer, nothing is obligatory upon him; his prayer is valid.

Hazrat Sha’bah says that I asked Hazrat Hakam and Hazrat Hammad about the person who forgets to recite the Tashahhud. They replied, “Can everyone recite the Tashahhud perfectly? His prayer is valid.”

Hazrat Abdullah bin Shaddad narrates that once Hazrat Abdullah bin Umar (may Allah be pleased with them) did not sit after two rak'ahs, so he recited the Tashahhud twice at the end of his prayer.

Hazrat Muhammad bin Ali (may Allah be pleased with him) says that if a person sits for the duration of Tashahhud and then his ablution breaks, his prayer is complete because not everyone can recite the Tashahhud properly.

Hazrat Umar says that prayer is not valid without Tashahhud.

Hazrat Ibn Umar (may Allah be pleased with them both) says that in every prayer there is recitation, sitting after two rak'ahs, tashahhud, and saying salam. If you did not do so, then after saying salam, sit and perform two prostrations.

Hazrat Umar says that prayer is not valid without Tashahhud.