There is a wolf and a lamb that inhabit our hearts and which are eternally on dispute. The wolf living inside of us is called flesh, and it is our selfish and sinful nature. The lamb, on its side, is called spirit, human's natural tendency of walking towards his creator.
You see, we know for a fact that by its own nature, the lamb is weaker than the wolf; the latter is, naturally, a predator of the former. Looking at it this way makes it easier to understand that we don't have to feed the wolf so that it remains strong and beats the lamb in their daily fights, more than that, in the struggles that we face every time we have a decision to make.
No! On the contrary, we must keep him chained and shackled at all times, for it is not a domesticable animal that we can carry around on our laps, or even walk with using a leash as we would with a pet... This way it could easily devour the lamb.
The lamb, this one should be well fed and taken care of so that it gets stronger and stronger and may resist the inevitable strikes of our inner wolf that, as weak as it may seem, will never be completely dead.
This illustration serves to teach us that we must feed the things that generate good in our hearts, be them thoughts, attitudes and actions, the things that honor and please God and overflow, become practical love towards our neighbors. Whatever we feed gets stronger and multiplies on our lives, be it selfishness, our vices and flaws, be it compassion, our virtues and unselfish works.
Nevertheless, we must realize that even the strongest of all the lambs is still, by its own fragile nature, unable to match the weakest of the wolves. For its safety, then, we need the shepherd to drive away the wolf that keeps on attacking. In this story the shepherd is Christ, on the person of the Holy Spirit that lives in each and every one of God's sons, being the supernatural strength that we need in order to overcome our own limitations and natural weaknesses, and the onset of the enemy.
May God bless us every day, making us able to seek in Him the strength that we lack to subdue ourselves on the struggles of every day. That in this search we can recognize our deepest need and total dependency on Him. That, finally, may we surrender our life history to the good shepherd that is Christ, who not only will take good care of our inner lamb, but also will help us keep our wolf under control, and even when we can no longer keep it tied up, He will sure come to our help and support.