The question is "Why?" Why do any penance at all? Letís face it, suffering, sacrifice, self-denial is repugnant to us humans. We all like comfort, convenience and instant gratification. We like the easiest way out of trouble. We like no trouble at all, actually. We donít want to be bothered and we donít like not getting our own way in everything.
The answer to "Why do penance?" is really quite simple. Jesus said: "Whoever wishes to come after Me must deny himself, take up his cross and follow Me" (Matthew 16:24). Denying ourselves, doing penance is NECESSARY for salvation.
I often compare SPIRITUAL self-denial with the physical, emotional and psychological self-denial that Olympic athletes undergo. Athletes know that sitting around home day after day, eating junk food and watching TV is NOT the way to strengthen themselves for an Olympic competition. Consider what athletes endure in hopes of winning a gold medal. They watch their diet carefully; they practice for hours every day; they exercise to strengthen themselves totally: they FOCUS on the prize. These athletes discipline themselves to the hilt in hopes of winning an earthly honor. There certainly is nothing wrong with this enterprise, but we can learn from these athletes a valuable lesson of the spiritual life. We humans are made of two parts: body and soul. It is sensible that we take reasonably good care of our physical health because we are then able to live and work in service of God and others. (This doesnít mean that handicapped people cannot do this, as well, but by their condition, they achieve holiness by accepting and adjusting their lives to their situation.)
But attention to "strengthening" our spiritual lives is even more important than that of our physical lives. Spiritual self-denial and discipline tones our spiritual muscles (virtues). Lack of spiritual self-denial and discipline leaves us spiritually flabby and easy prey to temptation and sin. It is as simple as that.
Yet denying ourselves is not an end in itself. It is a MEANS to an end: our eternal happiness in Heaven. Flabby, undisciplined bodies do not win races. Souls who do no denying of oneself for the sake of the Kingdom, donít make it there. Jesus said so. So how should we deny ourselves? Surely we can "give up" the old stand-bys: candy, soda pop, TV, movies. But actually, the best discipline and penance we could do is simply doing our every day duties as best we can, with as much love for God and our neighbor that we can with the help of Godís grace, with prayer and in imitation of Jesus.
That seems too uncomplicated, doesnít it, yet, Our Lady of Fatima encouraged us just in this way. Putting up with what life dishes out every day with patience and love for God is a quick way to holiness. Many saints achieved spiritual greatness just this way. Happy self-denial!!!
God bless you!