Obligation of invoking Allah's Blessings upon the Prophet in the final Tashahhud

Q 8: Is Al-Salat-ul-Ibrahimiyyah (the second part of the Tashahhud: invoking Allah's Blessings and Peace upon the Prophet) obligatory? What is the ruling on a praying person who abandons it intentionally or forgetfully? Will this invalidate one's Salah?

A: Al-Salat-ul-Ibrahimiyyah in the last Tashahhud (testification recited in the sitting position in the last unit of Prayer) is obligatory according to the more correct of the two scholarly opinions. The Prophet (peace be upon him) is reported to have commanded it be done. Accordingly, a praying person who forgets to say it should perform Sujud-ul-Sahw (Prostration of Forgetfulness), whether they are Imam (the one who leads congregational Prayer) or Munfarid (person offering Prayer individually). If a worshiper abandons it intentionally, their Salah will be invalid.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.