Relapse

I am not sure what started me down this path of thought today..(in other words this is your warning that I am processing as I am writing this). Earlier this evening I was having English conversation "time" with a new friend of mine. We spent about 3 hours in Starbucks talking about everything from his experience growing up in East Berlin before the wall came down to the issue of teen pregnancy in the U.S. At some point I was sharing how I believed everyone has "their thing." (he is not a believer) This "thing" represents a particular weakness or sin that we are particularly susceptible too, and must trust God to help us guard against. For some it is drinking, or drugs, pornography or other sexual sins. Or it might be something equally damaging but less threatening initially, like comparing ourselves to others and either being crippled by low self-worth..or pride.
Anyway..tonight I was reading out of one of my new favorite books. It is old actually- it is a book of C.S. Lewis poetry that I got for Christmas. One of the first poems that the book fell open too tonight leaped out at me:

"Out of the wound we pluck
The shrapnel. Thorns we squeeze
Out of the hand. Even poison forth we suck,
And after pain have ease.

But images that grow
Within the soul have life
Like cancer and, often cut, live on below
The deepest of the knife,

Waiting their time to shoot
At some defenceless hour
Their poison, unimpaired, at the heart's root,
And, like a golden shower,

Unanswerably sweet,
Bright with returning guilt,
Fatally in a moment's defeat
Our brazen towers long-built;

And all the former pain
And all our surgeon's care
Is lost, and all the unbearable (in vain
Borne once) is still to bear.

So when you read this, what do you think "images that grow within the soul," means? This poem gives me a few things to think on, and I am not going to share all of them right now; but one is, what about the heart issue stuff? The deep stuff, the cancer in our blood that shapes us- and whether we realize it or not silently dictates much of reaction and responses? This poem paints for me a very poignant picture of what sin does to me when I allow it to linger in my heart. It takes root. It grows under the surface. And it could cripple me with guilt and shame, or perhaps harden my heart so that I don't recognize it's presence.
I don't think I have the right words to express how thankful I am that Christ the "Living Water" is ready and willing to wash that cancer away from us each time, if we are willing to relinquish it, or perhaps first even acknowledge it's existence. I think it cheapens the process of healing and redemption if we think we are not susceptible to it forever after. We are clean, we are free, but we must also not forget it is waiting to again shoot it's poison at us in some "defenceless hour."
I feel that I have been challenged to really re-think upon when my "defenceless hours" may be... When am I the most vulnerable?