Ethics of a Sandwich

So today I was walking to school
(oh I know I've been ignoring the 3 beautiful things - well not ignoring just forgetting - but hey I went a month I think which ain't bad for a resolution)

Anyway I was walking and I passed a homeless guy and he asked for change, and I automatically said I was sorry, and kept walking. I got about halfway down the block and then I thought I'm such a hypocrite, I have a sandwich I just made for my lunch in my backpack. So I went back and offered it to him, and he was grateful (which was nice - downtown sometimes when we offered food we got laughed at or spit on). Turned out the pear I'd brought was bad, so I didn't have any lunch, in the end. But that was fine, since I don't go hungry most days, and that guy probably does. He was sweet to say he didn't want to take my lunch, but I honestly replied that I could get more food if I needed it.

So anyway I felt really good after I walked away. He'd asked me if I went to Fuller, which means others of my peers have probably talked to and helped him out. I was pleased with myself for not being a big ol' loser who walks by a hungry person with food in my backpack.

And then I started overanalyzing it all, as I am wont to do, and I realized that maybe I was feeling too good and had in fact fallen into a sinful pride over the whole thing. Perhaps I had ruined the good deed by puffing myself up over it.

We've been studying Luther's ethics and how he says you should feed your neighbor because he's hungry, not to please God. And I think he's got a point. I fed the guy because he needed lunch. I don't discount myself in God's eyes by feeling good about myself, no more than I upped my standing with God by doing it in the first place.

Yet I was still bothered. Would Luther say one should stop doing good deeds until one can do them with a pure heart? If a good deed will cause one to sin (by feeling pride), should one not do it? Or is none of this actually pride, or maybe not bad pride (is there good pride)?

Anyway I posed the question to my prof so we'll see what he says. Meantime, that's my dilemma today. And now I've made it all that much worse by telling you when I'm not supposed to go about trumpeting my deeds.

Sigh. I'm a piece of work.

UPDATE

Prof's response:
"No, I think he'd say, of course you did it with pride -- you're a sinner justified by Christ, that's just what sinners do.
This is a perfect illustration of Luther's dictum, Sin boldly, but believe in Christ more boldly still."