The Eightfold Path seems to be very much a systematization of spiritual experience. The claim is, if you just do A + B + C + D you will get to Enlightenment. It's spiritual math.
In a lot of the contemplative traditions there is a tension between forming yourself (i.e. disciplining yourself morally, willing your mortification, "right effort" in the Buddhist path) and being formed (i.e. letting the meditative practice, or God, from some points of view, "do It's work").
Theravada Buddhism is more on the "forming yourself" end of the spectrum. Karma is an immutable law. The effort you put in is what you will get out. The meditative practices do need to "act on you," but the emphasis is more on personal effort.
In the Christian tradition, we can open ourselves, we can prepare our spirits, but at the end of the day we are dependent upon the work of God for transformation:
"Then why is this work so toilsome? The labor, of course, is in the unrelenting struggle to banish the countless distracting thoughts that plague our minds and to restrain them beneath that cloud of forgetting which I spoke of earlier. This is the suffering. All the struggle is on man’s side in the effort he must make to prepare himself for God’s action, which is the awakening of love and which he alone can do. But persevere in doing your part and I promise you that God will not fail to do his."
"Now, very briefly, I must just touch on the means for reaching this state. Here, again, it has been constantly stressed that the means do not consist in mental activity and discursive reasoning. They consist in what Roger Fry, speaking about art, used to call 'alert passivity,' or in what a modern American mystic, Frank C. Laubach, has called 'determined sensitiveness.' This is a very remarkable phrase. You don’t do anything, but you are determined to be sensitive to letting something be done within you."
– Aldous Huxley, Symbol and Immediate Experience, The Divine Within
There is certainly also a tension in the Christian tradition. We are responsible for our moral lives. We are responsible for putting ourselves in a place for God to act. But in the end, true transformation has to come passively. It has to be a gift.
Personal effort and "alert passivity" are required in both paths. It's a matter of emphasis.