Numbers 33:39

And Aaron was an hundred and twenty and three years old when he died in mount Hor.

Cross-references

Numbers 20:25 Historical context

Numbers 33:39 adds Aaron's age at death; Numbers 20:25 commands his ascent to Mount Hor where he died.

In Numbers 20:28, Aaron's death on Mount Hor is described in detail, including the transfer of his priestly garments to Eleazar.