Jamieson, Fausset and Brown on Exodus 1:9-10

9-10. he said ... Behold, the ... children of Israel are more and mightier than we--They had risen to great prosperity--as during the lifetime of Joseph and his royal patron, they had, probably, enjoyed a free grant of the land. Their increase and prosperity were viewed with jealousy by the new government; and as Goshen lay between Egypt and Canaan, on the border of which latter country were a number of warlike tribes, it was perfectly conformable to the suggestions of worldly policy that they should enslave and maltreat them, through apprehension of their joining in any invasion by those foreign rovers. The new king, who neither knew the name nor cared for the services of Joseph, was either Amosis, or one of his immediate successors [Osburn].