Deuteronomy 32:50

And die in the mount whither thou goest up
Immediately after having taken a view of the land, expect to die, prepare for it, and willingly and cheerfully submit to it:

and be gathered unto thy people;
to the spirits of just men made perfect in heaven, his more immediate and more remote ancestors, the souls of good men; for otherwise there were none that died, and were buried here, before him, and therefore can have no respect to the buryingplace of his people:

as Aaron thy brother died in Mount Hor, and was gathered unto his
people;
of which Moses was an eyewitness; and which is observed, because there was a great likeness between the death of him, and what Moses was now called to, both as to the place and manner of it; and likewise the cause of it, later mentioned; as also to make death more easy and familiar, and less terrible to him, when he cared to mind how calmly, cheerfully, and comfortably, his brother Aaron died; see ( Numbers 20:25-29 ) .