AND BALAK THE SON OF ZIPPOR SAW, ETC. What did he see? He saw both through the window of wisdom and with his physical eyes. The tails of the skirts of the stars are the windows of wisdom, and there is one window through which the very essence of wisdom can be seen. So Balak saw with his own particular wisdom.
Balak Sees Israel Through the Windows of Stars
Zohar, Balak 1:1