"and Moses, Aaron and Chur went up to the top of the hill": as we mentioned: to bring to mind the deeds of the patriarchs and the matriarchs, viz. (Numbers 23:9) "for from 'the peaks of the rocks' (the patriarchs) I see him; from 'the hilltops' (the matriarchs) I gaze upon him."
Moses, Aaron and Chur Went Up to the Top of the Hill
Mekhilta Tractate Amalek 1:24