Is it permissible for me to add "alone, without partner" to the formula of the Tashahhud that I recite: "All greetings are for Allah, all pure things are for Allah, all greetings and prayers are for Allah. Peace be upon you, O Prophet, and the mercy of Allah and His blessings. Peace be upon us and upon the righteous servants of Allah. I bear witness that there is no god but Allah, and I bear witness that Muhammad is His servant and His Messenger," so that it becomes: "I bear witness that there is no god but Allah alone, without partner, and I bear witness that Muhammad is His servant and His Messenger"?

The mentioned wording for the tashahhud is that which was authentically reported from 'Umar ibn al-Khattab, may Allah be pleased with him, and narrated by Imam Malik. It includes: "All greetings are for Allah, all purifications are for Allah, all good deeds and prayers are for Allah. Peace be upon you, O Prophet, and the mercy of Allah and His blessings. Peace be upon us and upon the righteous servants of Allah. I bear witness that there is no god but Allah. And I bear witness that Muhammad is His slave and His Messenger."

The addition of "alone, without partner" was reported in 'Umar's tashahhud by Al-Hakim, but its chain of narration is weak due to its discontinuity between 'Urwah and 'Umar, and an error by 'Abd al-'Aziz ibn Muhammad. The preserved wording from 'Umar is that which Malik narrated without this addition.

Imam Malik was not known to have included this addition in 'Umar's tashahhud that he chose. However, this addition has authentic supporting evidence in other tashahhuds reported from the Prophet, peace and blessings be upon him, such as what was narrated from Ibn 'Umar and Ibn Mas'ud, which indicates its validity in tashahhud formulas generally.

Therefore, there is no blame on whoever says in their tashahhud: "I bear witness that there is no god but Allah alone, without partner, and I bear witness that Muhammad is His slave and His Messenger," even if their tashahhud is the one reported from 'Umar. It is better to adhere to the formulas authentically reported from the Companions, because the variation in the formulas of dhikr (remembrance) and acts of worship is permissible, and they can be performed in various ways, as mentioned by Ibn Taymiyyah.