Praise be to Allah, and peace and blessings be upon the Messenger of Allah.
There is nothing wrong with referring to the Prophet Muhammad ﷺ as “Our Master Muhammad”, because he is the master of the children of Adam and the master of the servants of Allah and the messengers.
It is authentically reported that he ﷺ said:
“I am the master of the children of Adam, and I do not boast.”
Therefore, there is nothing wrong with a Muslim saying: “Our Master Muhammad ﷺ”, or: “O Allah, send prayers and peace upon our master Muhammad”, because he ﷺ is the master and leader of creation, and the beloved friend of the Most Merciful.
As for what was reported concerning disliking the use of this expression during his lifetime ﷺ, this was in order to prevent the means leading to exaggeration concerning him. When some people said to him, “You are our master,” he said:
“The Master is Allah, Blessed and Exalted.”
The Prophet ﷺ feared that people might go beyond the proper limits in praising and venerating him.
After his death ﷺ, and after it was established that he is the master of the children of Adam, there is no objection to saying: “Our Master Muhammad ﷺ.”
As for other people, it is preferable not to address a person by saying “O our master”, because avoiding this is further removed from causes of arrogance and exaggeration, and because the Prophet ﷺ said:
“The Master is Allah, Blessed and Exalted.”
However, it is permissible to describe a person as “the master of his people” or the master of his group when this means that he is their leader, foremost among them, or holds a recognized position of status among them.
There are examples of this in the Sunnah. The Prophet ﷺ said about Al-Hasan, may Allah be pleased with him:
“Indeed, this son of mine is a master.”
He ﷺ also said:
“Who is the master of the tribe of so-and-so?”
And when Sa'd ibn Mu'adh, may Allah be pleased with him, came to judge regarding Banu Qurayzah, the Prophet ﷺ said to the Companions:
“Stand up for your master.”
This type of usage is permissible because it refers to leadership, status, or virtue, rather than exaggeration concerning the person.
Therefore, it is preferable when addressing people to say “our brother”, “O Abu so-and-so”, or similar expressions.
But if one says: “So-and-so is the master of his people,” or “Who is the master of the tribe of so-and-so?”, there is nothing wrong with this when what is meant is leadership, precedence, or an established position.
Likewise, if the word “master” is applied to someone because he is known for virtue, knowledge, reform, generosity, and good character, there is nothing wrong with that, provided there is no fear that such praise will lead him to arrogance or self-admiration. If that is feared, then such praise should be avoided.
It is not necessary, when saying “the master of the tribe of so-and-so,” that the person be righteous. If he is immoral or a hypocrite, he may still be the master of his people in terms of leadership, and it is permissible to say “the master of the tribe of so-and-so” in that sense, without this constituting praise of his religion or righteousness.
As for naming human beings with some names that occur among the Names of Allah, they are not all subject to the same ruling.
Some of Allah’s Names are exclusive to Him, and therefore they may not be used for created beings, such as:
Allah
Ar-Rahman (the Most Merciful)
Al-Khallaq (the Supreme Creator)
Ar-Razzaq (the Provider)
Lord of the Worlds
And whatever names and attributes are exclusive to Allah.
Thus, a person should not be called “Allah,” “Ar-Rahman,” “Al-Khallaq,” “Ar-Razzaq,” or any other name that is exclusive to Allah, Glorified and Exalted.
As for names that can be applied to Allah and to some of His creation, it is permissible to name a person with them when the intended meaning is one appropriate to a created being.
Examples include Aziz, Basir, and Hakim, and similar expressions.
Allah says:
“Then We made him hearing and seeing.” [Al-Insan 76:2]
And He says:
“And the wife of Al-Aziz said...” [Yusuf 12:51]
Allah has therefore described some of His creation with attributes and expressions that share the same basic wording as descriptions applied to Himself. However, what is attributed to Allah is perfect and absolute, whereas what exists in the created being is limited and appropriate to its nature.
Thus, one may say: “So-and-so is respected among his people,” “So-and-so is perceptive about matters,” or “So-and-so is wise,” when the intended meaning is appropriate to a human being.
A created being possesses only a limited share of such meanings, whereas Allah, Glorified and Exalted, possesses absolute perfection in them, in a manner unlike the perfection of created beings.
It is permissible to say “Our Master Muhammad ﷺ” because he is the master of the children of Adam and the master of the messengers.
As for addressing someone other than the Prophet ﷺ by saying “O our master,” avoiding this is preferable, while it is permissible to say “the master of the tribe of so-and-so” or “the master of his people” when what is meant is leadership, precedence, or recognized status.
The Names of Allah are not all the same. Names that are exclusive to Allah should not be used for created beings, such as Allah, Ar-Rahman, Al-Khallaq, and Ar-Razzaq. Names that share their basic wording and meaning between the Creator and created beings, such as Aziz, Basir, and Hakim, may be used for a created being in the sense appropriate to that being.
And Allah knows best.