In most cases, a "master" in the Bible refers to truth. That can vary according to the person being called master -- Egyptian masters respresent factual, worldly knowledge; when the Lord is referred to as master it means Divine Truth itself. The term does vary according to context. If the things directed by the "master" represent knowledge and ideas, the master will represent desires for good, since desires for good are the things that inspire true thinking.

350. Verse 4 And Abel brought some of the firstborn of his flock and of their fat; and Jehovah had respect for Abel and his gift.

Here, as previously, 'Abel' means charity. 'The firstborn of the flock' means the holy which is the Lord's alone. 'Fat' means the celestial itself, which also is the Lord's. 'Jehovah had respect for Abel and his gift' means that things constituting charity, and all worship deriving from it, were acceptable to the Lord.