The pairing with Parashah Vayeshev, whose central episode is Joseph sold by his own brothers to passing traders for silver, rests on Amos's opening condemnation of a people who sell the righteous for silver and the needy for a pair of sandals, language close enough to Joseph's own sale that the connection has been read as deliberate since ancient times, even though Amos never names Joseph directly in this particular verse.
Where the parashah tells Joseph's sale as a specific family betrayal, driven by jealousy over their father's favoritism and Joseph's own dreams of future authority over his brothers, Amos generalizes the same transaction, a human being's worth reduced to a trivial price, into a standing social crime the prophet condemns across the whole nation centuries later, treating Joseph's brothers' betrayal as the founding instance of a pattern that never fully disappeared.
The haftarah's closing argument, that the prophet must speak because God has spoken, mirrors a quieter thread within the parashah itself: Joseph, sold into slavery through no fault of his own, nonetheless rises through Potiphar's household and eventually Egypt's own government, a pattern the tradition reads as evidence that what people intend for harm, providence can still turn toward an unlooked for outcome.