The brothers were terrified. So they did what frightened children do — they invoked the father. "Thus shall you say to Joseph: forgive now the guilt of thy brethren and their sin, for they committed evil against thee. But forgive, I beseech thee, the guilt of the servants of the God of thy father."
The Targum Pseudo-Jonathan on Genesis (50:17), a tannaitic-era Aramaic translation enriched with midrashic expansion, preserves the plea almost word for word from the Hebrew. What the Targum highlights is the hinge the brothers lean on: they do not ask as sons of Jacob. They ask as servants of the God of Jacob.
This is the quiet genius of their appeal. They know Joseph loves their father. They know, too, that Jacob's God is now Joseph's God. So they stack the appeal carefully. First: forgive for our father's sake. Second: forgive for the sake of the God our father served. They are asking Joseph to rise above personal memory and answer to something higher than memory.
And Joseph wept.
The Targum does not explain the tears, but the sages who carried this text — and later rabbis who would cite it across our 2,900+ texts from <a href='/categories/midrash-rabbah.html'>Midrash Rabbah</a> — understood them. Joseph wept because he realized the brothers had never truly believed the earlier reconciliation. All these years, they had lived in his house the way a guest lives in a rented room: carefully, always packing.
The takeaway: forgiveness given once may need to be given again, and again, until the one being forgiven can finally unpack.