Adam Clarke on Habakkuk 3:16

When I heard, my belly trembled - The prophet, having finished his account of the wonders done by Jehovah, in bringing their fathers from Egypt into the promised land, now returns to the desolate state of his countrymen, who are shortly to be led into captivity, and suffer the most grievous afflictions; and although he had a sure word of prophecy that they should be ultimately delivered, yet the thoughts of the evils they must previously endure filled his soul with terror and dismay; so that he wishes to be removed from earth before this tribulation should come, that his eyes might not behold the desolations of his country.

When he (Nebuchadnezzar) cometh up unto the people, (the Jews), he will invade them (overpower and carry them away captive) with his troops.