What is the ruling on saying "Sayyiduna" (our master) to the Prophet and the Awliya (saints), and on being named with the Beautiful Names of Allah?

It is permissible to use the term "Sayyiduna" (our master) for the Prophet, peace and blessings be upon him, because he is the master of the children of Adam. He himself, peace and blessings be upon him, said it, but he disliked people using it during his lifetime for fear of exaggeration (ghuluw). After his death, peace and blessings be upon him, there is no harm in saying "Sayyiduna." As for other people, it is preferable not to call them "Sayyiduna" except in an attributive sense, such as "Sayyid al-Qawm" (master of the people) or "Sayyid al-Qabilah" (master of the tribe). It is better to say: "Ya Akhana" (O our brother), "Ya Aba Fulan" (O father of so-and-so). If there is fear that calling someone "Sayyid" might lead to arrogance on their part, then that should be avoided. This term should not be used for a disbeliever, a hypocrite, or a disobedient person. Rather, it is for an elderly sheikh or a knowledgeable jurist known for goodness.

As for the names of Allah the Almighty, they are of two types: those that are permissible to use for naming, and those that are not. So, one should not say "Khallaq" (the Creator) or "Razzaq" (the Provider), or "Rabb al-Alamin" (Lord of the Worlds). However, names like "Aziz" (Mighty) and "Basir" (All-Seeing) are permissible; because they are shared, and the created being has a share in them, while Allah, Glory be to Him, has the most perfect share of them. However, names specific to Allah should not be applied to anyone other than Allah.