This is an excerpt from "Letter II" from "Letters from a Stoic" by Seneca (translated by Robin Campbell).
Seneca's use of figurative language is exemplary.
The abstract becomes concrete through metaphor in Seneca's writing.
Seneca clarifies by carrying over meaning from one word to another.
That's part of his style.
There is no waste in Seneca.
Each word is made to work inside tight sentences.
Sentences so tight they leave no room to doubt.
Seneca's thoughts and writing are magically current.
Maybe it's because he's addressing universal issues, which plague us as much today as they did yesterday.
Or maybe it's the language he employs.
Whatever it is, you feel he is talking to you.
And only you.
It is as if he knows you, and, out of friendship, he decides to share his avuncular wisdom with you.
Someone once defined a classic as something that always appears contemporary, irrespective of when it was written.
Although Seneca was born at around the same time as Christ, his writing has not aged.
His words seem to exist in a space and a time all of their own.
"Judging from what you tell me and from what I hear, I feel that you show great promise. You do not tear from place to place and unsettle yourself with one move after another. Restlessness of that sort is symptomatic of a sick mind. Nothing, to my way of thinking, is a better proof of a well ordered mind than a man's ability to stop just where he is and pass some time in his own company.
Be careful, however, that there is no element of discursiveness and inconsistency about this reading you refer to, this reading of many different authors and books of every description. You should be extending your stay among writers whose genius is unquestionable, deriving constant nourishment from them if you wish to gain anything from your reading that will find a lasting place in your mind. To be everywhere is to be nowhere. People who spend their whole life traveling abroad end up having plenty of places where they can find hospitality but no real friendships. The same is necessarily the case with people who never set about acquiring an intimate acquaintanceship with any one great writer, but skip from one to another, paying flying visits to them all. Food that is vomited up as soon as it is eaten is not assimilated into the body and does not do one any good; nothing hinders a cure so much as frequent changes of treatment; a wound will not heal over if it is being made the subject of experiments with different ointments; a plant which is frequently moved never grows strong. Nothing is so useful that it can be of any service in the mere passing. A multitude of books only gets in one's way. So if you are unable to read all the books in your possession, you have enough when you have read all the books you are able to read.
And if you say, 'But I feel like opening different books at different times,' my answer will be this: tasting one dish after another is the sign of a fussy stomach, and where the foods are dissimilar and diverse in range they lead to contamination of the system, not nutrition. So always read well-tried authors, and if at any moment you find yourself wanting a change from a particular author, go back to ones you have read before.
Each day, too, acquire something which will help you to face poverty, or death, and other ills as well. After running over a lot of different thoughts, pick out one to be digested thoroughly that day. This is what I do myself; out of the many bits I have been reading I lay hold of one."