And Jacob called unto his sons, and said, Gather yourselves together, that I may tell you that which shall befall you in the last days.
Read Chapter 49
Ambrose of Milan
After the joyous conferral of this blessing, Jacob called his sons as well. Whereas before he had preferred the younger to the elder, he begins with the eldest. In the former case he preferred the symbolic gift; in this one he maintains the order of age. Likewise earlier he had blessed all men with all their posterity and offspring of times to come in the persons of the two brothers; a repetition of that blessing of the people might seem superfluous, or the earlier blessing might be considered invalid. And so it is with reason that Jacob says he is presenting anew his announcement of events that were to come in later ages, rather than a blessing.
Last. Hebrew, "future days. "It was an ancient and commendable custom, for parents to assemble their children in their last moments, to give them salutary instructions. They often also foretold to them what should happen. See Deuteronomy xxxi; Josue xxiv; 1 Kings xii; Tobias iv. 3; 1 Machabees ii. Cyrus and Socrates both believed that they had then an insight into futurity. (Calmet)
This is a prophecy and not a blessing. In fact, the blessing is concerned with someone who is blessed, while the prophecy is fulfilled when a certain action is accomplished. How will the explanation proposed above agree with these words of the Scripture: “All these are the twelve tribes of Israel; and this is what their father said to them as he blessed them, blessing each with the blessing suitable to him.” At one time are they clearly prophecies, at another prophecies called blessings? In this explanation it must be understood that exactly in the things said are the prophecies and the blessings, so that the blessings fall on the one who was born from Judah, on the one who was prefigured by Joseph, on the one who, coming from Levi, finds himself being the priest of the Father, while the prophecies fall on those who acted as enemies and had no consideration for the Son of God.