Or HaChaim on Genesis 50:16/אור החיים על בראשית נ׳:ט״ז

1 ויצוו אל יוסף, they ordered emissaries to tell Joseph, etc. We again have to explore the meaning of the word לאמור in this context. If it means that the emissary were to speak to Joseph, the Torah should have added the words אל יוסף. Perhaps the brothers did not want the emissary to tell Joseph that the brothers had sent them but to tell him that he himself had overheard their father command the brothers to tell him of this conversation at the appropriate time. This would account for the word לאמור being used twice in this verse.