Here's one area I'm still working on:
1505 Moved by so much suffering Christ not only allows himself to be touched by the sick, but he makes their miseries his own: "He took our infirmities and bore our diseases." But he did not heal all the sick. His healings were signs of the coming of the Kingdom of God. They announced a more radical healing: the victory over sin and death through his Passover. On the cross Christ took upon himself the whole weight of evil and took away the "sin of the world," of which illness is only a consequence. By his passion and death on the cross Christ has given a new meaning to suffering: it can henceforth configure us to him and unite us with his redemptive Passion.
I mention it because I had an opportunity to put this into practice today. I think one of the areas I stumble when it comes to offering up suffering to God is the notion (completely my notion) that it has to be something big (death, disease, assorted mayhem). Most of the time, we're not dealing with the big stuff, but with mountains of little stuff. Work stuff, home stuff, family stuff, commuting stuff--it's all there, every day, just waiting for us to do something more positive than merely complaining about it.
My daughter has had some kind of bug for almost two weeks. It's one of those things that seems to come and go. It's affected her appetite (and without getting to graphic, it's had a major gastric component to its unpleasantness) and her sleep patterns, which in turn has affected our sleep patterns. Last night was the third night out of five that she had awakened around two in the morning. Unfortunately, last night she woke us up to tell us she'd gotten sick. I helped clean things up and went back to bed; my wife stayed up with her for several hours. She got sick again, and Stacey had to go through the whole cleanup routine a second time.
Julie came into our room around 7:00 this morning. I got up with her because Stacey was desperately sleep-deprived. Stacey got up a while later and we had breakfast; she went back to bed and I spent some time trying to help Julie feel better.
Oh, did I mention the bathroom sink thing? No? The bathroom sink got clogged for the umpteenth time (it's a 40 year old house, and the pipes are in a somewhat fragile state). When this happens it actually takes both upstairs bathroom sinks out of commission, because they share a common drain pipe. the downstairs bathroom is currently gutted, so it left us with only one working sink in the entire house (the kitchen).
I plunged for a good half-hour, but to no avail. I was trying to avoid using drain cleaner (the plumber had said to stay away from it), so I went to Home Depot and got an auger. The instructions indicated that I could use it without taking the trap off (even though I knew the clog was past the trap). While I was trying to get the head of the auger past the trap, it punched a hole in the pipe (it was corroded pretty much all the way through, so it didn't take much). I took off the trap and tried to use the auger to get at the clog. I'm pretty sure I didn't punch another hole in the pipe for which I'm grateful, but I also didn't get anywhere near the clog. Two more trips to Home Depot later (one for the new trap, and another one to get a second trap, since the first one I bought was the wrong size), I ended up duct-taping the old trap and putting it back on (since neither of the ones I bought actually fit). The old one now leaks from the fitting because the gaskets are so old. I finally surrendered and used drain cleaner, which took care of the clog in about 20 minutes.
While I was walking out of Home Depot for the third time, I took a moment to offer up my fatigue, my frustration, and my concern for my daughter. It didn't make me less tired or plumbing-weary, but that wasn't the point of doing it. The idea isn't to make it go away, but to use it positively--more importantly, to ask Jesus to use it.
Before I became a Catholic, suffering was mostly something to be avoided, and I was taught as a child that it was actually a sign of God's displeasure or one's own lack of faith. As a Catholic I've come to understand that suffering of all kinds (large and small, profound and trivial) is an invitation to enter into Christ's suffering, and thereby to know him better and participate in some wonderful mystical way with his own act of redemption. It's what Paul talks about in Colossians 1:24:
Now I rejoice in my sufferings for your sake, and in my flesh I am filling up what is lacking in the afflictions of Christ on behalf of his body, which is the church...
Clearly there is nothing lacking in Christ's suffering in terms ofsomething being deficient or missing. St. Paul is talking about the Lord giving us the opportunity--the privilege--of participating in his suffering by uniting it with our own.
There's a nifty explanation of the concept here, at http://www.scripturecatholic.com/.

