והכנעני אז בארץ. יתכן שארץ כנען תפשה כנען מיד אחר ואם איננו כן יש לו סוד והמשכיל ידום:

The Canaanites were then in the land: Perhaps the Canaanites captured the land of Canaan immediately thereafter (cf. Rashi ad loc). But if it is not so, then there is a secret to the matter, and whoever discerns it should be silent (i.e. keep it secret).