What I suggest is that habit is the ruler. And that one has the knowledge and ability to direct his or hers own will towards things they know are good.
One can direct his will into learning
Math, Physics, learning Torah, etc.
But it helps if there is some kind of numinous [holy] taste in what one is doing. There is luminosity in everything. One can serve God through everything.
This is the quote from that site:
The sublime spiritual sterility of the texts of Kant’s philosophical maturity, for instance, could scarcely provide a more perspicuous glimpse into the personality of perhaps the single most boring man ever to darken a wigmaker’s doorway. The leaden, caliginous bombast of Hegel’s prose was a pure emanation of his grindingly pompous soul. The turgidity of Derrida’s attempts at playfulness were little more than clinical specimens of his insufferable self-infatuation. As a general rule, to put it simply, if one wanders into one’s library in search of mirth, good fellowship, or wit, one does well not to seek out the company of the philosophers.