From activity that demands violence there is born zeal beyond measure.
St. Isaac the Syrian
To someone unfamiliar with St. Isaac, the word above could seem to be advocating physical violence against others. But that is not the activity nor the violence he is talking about. The activity he is talking about is ascetic and spiritual activity requiring a certain violence with oneself in order to accomplish it. For example, you may have to violently force yourself to fast or say prayers, or speak kindly to someone who annoys you. This violence is what the Gospels refer to when they say "The Kingdom of heaven suffers violence, and the violent take it by force."
Any growth in good requires a certain violence to oneself. You have to make yourself do the good that you know you should want to do, and you do want to do (at some level), but that you are just not motivated to do. There seems to be no energy for it. It doesn't come easily or even seem (at the moment) natural. You just have to force yourself to do it, sometimes with a force that borders on violence.
But this is not unreasonable. In just about any area of endeavour, a certain amount of self discipline, of violence to the self, is necessary to be successful. There were many a time in my student days when I had to violently grab myself and force myself to study even when nothing in me wanted to do it. Various work responsibilities, household chores, family obligations, and civic duties (filing and paying taxes come to mind) require that one force oneself to do them. And we do force ourselves--sometimes with merely minimal complaining--to do them because we know they must be done. They must be done to keep my job, for the house not to become a dump, to return love to those who have loved me, and to keep out of jail. They must be done, so we force ourselves. And having forced ourselves, we generally discover that what seemed so onerous to begin with, isn't nearly as bad as we feared, and sometimes even interesting or somewhat enjoyable.
When I was a teenager, I hated reading. Yes, it's true. I was (and still am somewhat) dyslexic and very hyperactive. The reward was just too small for the amount of effort it took me to focus my mind on page after page of text with no pictures. I was sixteen when I read my first book (with no pictures!). The book was Brother Andrew's God's Smuggler, and the stories were so engaging that I made it all the way through to the end--a feat I did not repeat until college, and still not often. I became a great skimmer and guesser through college and grad school--which served me well in most courses, but resulted in C-'s in lit classes ("You need to make more use of the text in your analysis," the prof would write under my C-. How could I? I hadn't read much of it).
But somewhere in my late twenties and early thirties I forced myself to start reading. Part of it had to do with work. I was teaching composition and I had no idea what I was doing: I read everything on the subject that I could get my hands on. Part of it had to do with the fact that we had to homeschool our children. Just because I didn't read didn't mean I wanted my kids to be ignorant. I had to read to know what to have my kids read (and to my surprise I discovered that classics are generally called that because they are well worth reading). And part of it had to do with my spiritual search. Although I met many wise and helpful guides along the way, there were no spiritual fathers. My spiritual fathers were found in old books, old books that eventually led me to the Orthodox Christian Church.
And now in my fifties I can't stop reading.
What's my point? My point is this: the discipline and struggle of the spiritual life and ascetic discipline is not much different from any other worthwhile activity in life. Once you make yourself do something long enough for it to become a habit, it comes to have meaning for you that you had never imagined. Or to use the words of St. Isaac, "there is born a zeal beyond measure," "from activity that demands violence."