Parashas Devarim
Devarim 2:31
Chabad.org — 2:31
Torah Temimah points to R’ Tanchuma — Yerushalmi Sheviit 6:1 (verified).
החל רש — עשיתי את ארצו חולין לפניך.
English: Begin to possess — I made his land ordinary before you.
Custom
Divine grant of the land.