Sforno on Genesis 37:25/ספורנו על בראשית ל״ז:כ״ה

1וישבו לאכול לחם, to demonstrate that what they had done was no crime in their eyes, or that the incident was not something that should interfere with their regular meal. When righteous people become aware of having inadvertently committed a sin, they not only do not celebrate it by eating, but they impose a fast day or more upon themselves. A prominent example of people imposing a fast day upon themselves, although they did not feel guilty for having done something wrong, were the Jewish tribes after having practically wiped out the tribe of Binyamin. We read about this in Judges 21,2-3 as well as about the fact that they imposed a fast upon themselves in spite of being convinced that they had done the right thing in going to war against that tribe. We also find something parallel when the King Darius threw Daniel into a pit full of starving lions. (Daniel 6,19). [The King had acted in accordance with the constitution of his country which demanded that a “heretic” such as Daniel be thrown to the lions, and the king’s efforts to have the law changed were rejected by his advisers. In spite of being legally correct, the king felt so badly that he went to bed hungry as a kind of penance for doing what was legally correct. Ed.] If the brothers sat down to eat immediately after throwing Joseph into the pit, this is clear evidence that in their minds they had certainly not committed any wrong. WE, who were not part of Yaakov’s household, and who know that these brothers were unanimously elevated to become the founding fathers of the Jewish nation, must therefore accept the premise underlying their actions as being that they had truly felt themselves personally threatened by Joseph, someone who was considered so mature that his own father had appointed him as manager over his senior brothers. The brothers had made strenuous efforts to put physical distance between themselves and Joseph in order to avoid any altercation. When he had sought them out in spite of their having signaled clearly that they wanted to avoid him, they felt understandably very threatened.

2הולכים להוריד מצרימה, these Ishmaelites were camel owners, they did not own the merchandise described which was carried by their camels. As soon as they would deliver the merchandise to the appropriate address in Egypt their mission was completed.