Q: What is the ruling on using the term of siyada (mastery/lordship) for the Prophet (may Allah bless him and grant him peace) in the prayer and outside of it?
Shaykh al-Shinqiti (may Allah have mercy on him) said: The hadith of ‘Do not call me a master in the prayer’ is fabricated and is also incorrect from the point of view of the Arabic language, because the correct form would have been ‘la tusawwiduni’ and not ‘la tusayyiduni’. But it did not come from the Prophet (may Allah bless him and grant him peace).
were made masters (sawwadathu) by the yellow and the red.
Shaykh Ahmad ibn Idris (may Allah be pleased with him), however, preferred not to say it inside the prayer.
For a full discussion on the different views of the scholars on this matter, see Sa’adat al-Darayn by al-qadi Yusuf al-Nabahani (may Allah be pleased with him).