A (Lost?) Teachable Moment with a Haredi Beggar at the Supermarket

As I wheeled my heavy shopping cart toward my car after procuring the victuals that would sustain my family of six for the week, I noticed a gentleman in Hasidic garb talking to another shopper, by all appearances asking for a dole. By the time I unlocked my car, he had made his way over to me and begun his charity pitch.

I said to him that if he would help me load my goods into my car, I would give him a tip. After a look of confusion briefly crossed his face, he agreed, and began placing bags into the car with alacrity. We conversed all the while:
Me: This is the way of the world, no? You work, you get paid.
Him: It's a mitzva to help out.
M: Indeed it is. After all, it says "when you see your enemy's donkey staggering under its burden..."
H: Chas Ve-shalom that we're enemies!
M: ...you didn't let me finish. Kal Va-chomer if it's your friend!
H: Exactly!

By that time, we had finished loading, and I reached into my wallet to offer a tip. He protested that he helped for the mitzva, not for the payment. I insisted that since I gave him the opportunity to fulfill a mitzva, he return the favor by giving me the opportunity to do a mitzva. He acceded and accepted my 10 NIS as long as it was clear to both of us that it was not in payment for his services.

I wonder, why did he so insist? Was it because he really didn't want the material reward to take away from his mitzva? Or was it because he was afraid to acknowledge the causal nexus between work and pay (it must be noted that 10 NIS for 2 minutes of manual labor is one hell of a welfare program)?

As my sister-in-law said, it was probably a little bit of both.

On that note, this "rabbinic yellow pages" has been making the rounds. Quite well done: