Yaakov is blessing Yosef’s sons and we see a striking similarity with the blessing his father gave him. We find an elderly father and an elderly grandfather giving a blessing to their offspring. Both have difficulty seeing. (Gen. 27,1; 48,10) In both cases the blessings are preceded with a kiss. (Gen. 27,27; 48,10)
In both narratives there is a person who attempts to change the blessing from the intended one to his brother. Rivka succeeds in getting the blessing intended for Esav to go to Yaakov. Yosef, on the other hand, tries to have his father give the blessing to Menashe the elder brother but fails and Yaakov insists on giving it to the younger one. In both occasions the blessing goes to the younger brother.
What is evident from these two episodes is that the eldest child does not necessarily gain privileges automatically. Yes, he has some benefits because of age, but the real blessings are not his without earning them. Every individual has a mission in life. Everyone’s function is different. Everyone has his own abilities and his own talent. He must strive to attain his mission and earn his privileges. His blessings will come to him when he succeeds.