I took a course on spiritual disciplines recently, and the professor was named Timothy. He loved to cite 1 Tim 4.7: Train yourself in godliness. He told us that this verse was his own life motto, or something along those lines: train yourself to be godly.
I am realizing, at a rate surpassing the rate of correspondence of my actions, that the athletic metaphor is uniquely apt for describing Christian life. You have to train yourself to be a Christian; it is something that requires the kind of intense, dedicated commitment and discipline a professional athlete would put forth in order to perform. You cannot take it easy, living life in auto-pilot, and be an athlete. It takes hard work and intentional effort. The same is true in the Christian life.
This means making room in our daily schedules for the spiritual disciplines. A football player might make room in his schedule for weight-lifting, film study, running and general aerobic exercises, etc. So also we have to make time for prayer, for Scripture readings and meditation, for fasting, for solitude, for confession of sins, and so on. You can't play sports without lifting weights, and you will only get as big as you lift. Likewise, we can only get as godly as we train ourselves to be. Christian experience is seemingly uniform on this matter: you will never be zapped with holiness.
There is another matter to consider here. I am a Seahawks fan. If you listen to their best players talk during interviews, like Russell Wilson or Earl Thomas III, you will hear them say things like: I believe in myself, in the talents God has given me, and with hard work and determination, I can accomplish anything. That "can do anything" attitude, that utter determination to be the best, is what empowers them to do wonderful, impressive things on the field. Why should it be any different with us as Christians?
2 Pet 1.3-4 tells us that God has provided everything we need to become participants in the divine nature. Everything needed for undergoing theosis is readily available to us, by God's grace and mercy. What remains is only that we make use of them. Why shouldn't we? And why shouldn't we give ourselves entirely to this end, fully convinced that with determination and God's gifts, we can make real progress? After all, we are no longer under sin but under God's grace (cf. Rom 6.11ff.).