“A person can make his property ownerless (hefker) in front of one person according to Torah law. And why did the Rabbis require making it ownerless in front of three people? So that one person can acquire it, and the other two people are witnesses.”
This is the opinion of Rabbi Yehoshua ben Levi on our daf, which is cited as the ruling in the Shulchan Aruch. (Orach Chaim 273:7) This need to declare the property ownerless in the presence of one or three other people seems to not be in accord with what we do regarding chametz before Pesach. When we do “bitul chametz” — nullification of the chametz — there is no requirement to do it in the presence of anyone else at all.
One approach to understand bitul chametz is that it is not a declaration of hefker, but rather a mental process of renouncement. As the Rambam writes, “One annuls it in his heart, considers it as dust, and should think in his heart that he has no chametz whatsoever. Any chametz in his possession is as dust and is purposeless.” (Laws of Chametz and Matza 2:2) Another approach is that any chametz does not really belong to the “owner” once it becomes forbidden for him to have any benefit from it on erev Pesach. The prohibitions against having “your chametz” on Pesach mean to not have chametz that “you want.” If a person does bitul, saying it in solitude or even via thought, he then does not “want the chametz” and therefore does not transgress. (Rabbeinu Nissim)
Working for Torah
“Rabbi Shimon took a basket on his shoulder and said, ‘Great is work, that it honors its owner’.”
The “Rabbi Shimon” mentioned in this statement in our gemara is “Rabbi Shimon bar Yochai”. However, Rabbi Shimon teaches elsewhere (Berachot 35b) that work is to be avoided since it takes away time and energy from Torah study. Perfection is achieved only through Torah. So, how can he praise the importance of work in our gemara when he carried a basket?
Answer: He was on his way to the Beit Midrash to learn Torah and he took the basket to sit on while he was learning instead of sitting directly on the ground. He would be able to learn Torah better in this way. His physical exertion of shouldering the basket was not for the sake of work, but rather for the sake of the Torah and for the honor of the Torah. (Maharitz Chiyos; also see Rabbeinu Nissim and Rabbeinu Asher)