Commentary for Genesis 50:17

שא נא לפשע עבדי אלהי אביך NOW, PRAY, FORGIVE THE TRESSPASS OF THE SERVANTS OF THE GOD OF THY FATHER — After having repeated to Joseph the words which his brothers stated had been their fathers message, “forgive thy brothers’ sin” the messengers were to add as a petition of the brothers “Now, pray etc.”, meaning “If you will not forgive them although they are your brothers, forgive them because they are the servants of the God of thy father”, implying though your father be dead, his God still lives and they are his servants.

ויבך יוסף בדברם אליו, “Joseph cried when they spoke to him.” He cried when he realized that they suspected him of harboring hostile thoughts against them. This verse is proof that Joseph had never informed Yaakov that the brothers had sold him, for if Yaakov had been aware of it, he would have ordered Joseph not to hold a grudge against the brothers on that account and to make up with them According to the Midrash, after Joseph’s original meeting with his father in Egypt, Joseph made a point of never again to meet his father without someone else being present so that his brothers would not have reason to suspect him of his telling his father that they had sold him.