The vast majority of words in the Russian language have different meanings, which sometimes are completely opposite. It depends on the specific context and method of application. To find out the meaning of the word "master", like many others, you need to use the explanatory dictionaries of the Russian language.
Ozhegov's Dictionary
It is one of the main collections, where a very large number of words are listed along with all their meanings. As well as examples of use.
The lord is a person from the upper strata of society. This is one who has real power over people depending on him (slaves, serfs). This name is often used for someone who has the power to dispose of something. It is in this context that such expressions as “the master of the situation” or “the master of his fate” are often used.
In addition, the gentleman is just one of the options for courteous treatment. In pre-revolutionary Russia, this was very common. Often you can find in letters, literature of those times the corresponding abbreviation "Mr.". Also used when mentioning someone. It is usually applied together with a rank or a surname.
Ushakov dictionary
You can find identical values in it. But there are some interesting additions.
Journalists often used this word and still use it in an ironic sense. In this case, the master is someone who does not deserve any respect. Sometimes a word in this meaning is also used in colloquial speech.
By the way, in pre-revolutionary times this word in the plural - "gentlemen" - was used as an appeal to several persons. Moreover, only men or men with women could be in the group.
The meaning of phraseology
When do they use the eternal phraseology “servant of two masters”, the meaning of which is rooted in the Bible? This is what they say about a person who is trying to simultaneously serve two or more people. This is done in order to obtain great wealth. Usually they say this about mercenary and duplicitous people.
The Bible speaks of the impossibility of simultaneously having all the blessings on earth and in heaven. Wealth is a blessing that can easily subjugate a person. It is important to be able to control it - to be his master, and not a slave. In order to gain all the blessings in heaven, you must stop constantly thinking about earthly riches and devote yourself to life with God. In the Gospel of Luke, one can read the statement that the true master is God. Serving him is the real wealth and goal of every believer. But serving both the Lord and Mammon (money, property), that is, two masters, is impossible.
The evangelical apostles Matthew and Luke also explain that two masters cannot be served simultaneously. Since both of them will not be able to relate equally well, they will not be able to be diligent in fulfilling assignments.
This approach served as an idea for the play of the same name by Carlo Goldoni. This story is about how the cunning and not too honest servant of Truffaldino served two masters with the aim of obtaining double benefits.