Many mephorshim pick up on this seemingly odd phrasing; first, the passuk already tells us that the blessings will come to us, so why do we need another verb to tell us that we’ll be receiving blessing, and second, v’hisigucha, is most commonly translated as ‘overtaken’ or ‘captured’ – aggressive verbs we don’t typically associate with blessings.
2. Rav Tzaddok HaKohen suggests that Moshe is giving us a bracha of anivus. An abundance of blessings and kindness from Hashem is wonderful, but we can’t let it alter who we are (for the bad), or blind us to forget our ideals and the truly important aspects of life. To quote, V’hisigucha is saying“vhisigucha bimkomcha“ = to keep you in your place; the place where you were before the blessings started pouring in. Newly-attained wealth should change and increase our tzeddaka-giving practices, but not change us into a haughty, unappreciative, ostentatious, egomaniac.
3. Rav Yisroel (Taub, I believe) of Modzitz understands v’hisigucha in terms of hasaga – mentalcomprehension and knowledge.
4. Finally, a related idea that came to mind is something I once heard explaining the difference between bracha and schar. On the surface, there doesn’t seem to be much of a difference between a blessing and reward…
A bracha, on the other hand is an ENABLER. It is a gift from Hashem that the recipient of the bracha is supposed to use to do enrich the world; a bracha is something you are supposed to harness and utilize for something great. The message being, take the blessings referred to by Moshe and Hashem, and let them ‘take you over,’ empowering us with the G-d-given abilities and skills to positively affect others and the world around us.