Rashi on Numbers 34:15/רש"י על במדבר ל״ד:ט״ו

1קדמה מזרחה — At the front of (קדם) the world which is the east; for the east side is called פנים, “the face" (equivalent to קדם, “front”), the west is called “behind”, and therefore the south is on the right and the north on the left (cf. Rashi on Exodus 27:13 and Note thereon).