Rabbi Soloveitchik makes an interesting observation about Yakov Avinu in this week’s Parsha. He comments on the words, אפרים ומנשה כראובן ושמעון, that Efraim and Menashe are to be considered as equal to Reuven and Shimon.
The Rav notes that Yakov is referred to as זקן in several instances. Yehuda says to his brothers that when the זקן calms down, we will speak to him about bringing Binyamin to Egypt. Yosef asks how their זקן father is doing. The Rambam writes that the זקן, Yakov, composed the ברוך שם כבוד מלכותו prayer. All of this is strange when Yakov died at 147 and Avraham and Yitzchak made it to 175 and 180.
The reason why Yakov is referred to as זקן and in some Jewish literature, ישראל סבא, is because he is the only one of the patriarchs who had a real relationship with his grandchildren. He was the first Jewish סבא. He taught Efraim and Menashe as well as his other grandchildren. He began the chain of והגדת לבנך ובן בנך, to tell it to our children and great grandchildren.
Throughout our history, this grandfather-grandchild relationship was very unique. All of this began with Yakov Avinu. This also explains the phrase בני בנים כבנים. Shabbat Shalom