Or HaChaim on Deuteronomy 33:13/אור החיים על דברים ל״ג:י״ג

1 מברכת ה׳ ארצו, "blessed of the Lord be his land, etc." Perhaps there is an allusion here to the time when the tribe of Joseph would complain to Joshua that it did not have enough land to support its population (Joshua 17,14). Moses blessed their land especially, i.e. that it be enlarged according to circumstances. Another reason the tribe of Joseph merited this special blessing was the fact that Joseph their founder had provided sustenance for all the brothers in Egypt. He who provides sustenance is considered as if he were the father as we know from Psalms 77,16 where the Psalmist speaks of "the sons of Jacob and Joseph" as if Jacob had had no other sons. Sanhedrin 19 explains that this unusual phrase is due to Joseph having been the provider.