Or HaChaim on Genesis 48:1/אור החיים על בראשית מ״ח:א׳

148.1. שני בניו עמו, את מנשה ואת אפרים, together with his two sons Menashe and Ephrayim. Why did the Torah have to give us the names of Joseph's two sons when we already know their names as well as the fact that he had only two sons? Alternatively, the Torah could have simply written: "Menashe and Ephrayim," and I would have known that these names referred to his two sons? Besides, why did the Torah have to insert the word עמו, with him, in the middle of the verse? Why did the Torah have to use the word את twice in this verse?

2Perhaps the Torah describes Joseph's desire that each of his children be the recipients of separate blessings in addition to the blessings that would devolve upon them in their capacity as his children. This is why it says separately: את שני בניו עמו.

3Perhaps the Torah wanted to inform us that Joseph's children deserved a blessing on two accounts; a) because of their respective virtues, b) because they were Joseph's children. The words בניו עמו refer to the latter, the words את מנשה ואת אפרים refer to their individual merits. The word עמו is interposed to prevent us from thinking that the Torah only wanted to inform us about the identity of these two sons.