Welsh History 101B:
My neighbour from England has come across raiding,
Slain six of my kinsmen and burned down my hall.
It cannot be borne, this offence and injustice:
I’ve only killed four of his, last I recall.
I’ll send for my neighbours, Llewellyn and Owain;
We’ll cut him down as for the border he rides.
But yesterday Owain stole three of my cattle,
So first I’ll retake them, and three more besides.
I didn’t get the meaning of “we’ll cut him down as for the border he rides”. Please can anybody explain?