Joshua 20:6
"And he shall dwell in that city, until he stand before the congregation for judgment, and until the death of the high priest that shall be in those days: then shall the slayer return, and come unto his own city, and unto his own house, unto the city from whence he fled."
Cross References (ranked by relevance)
Numbers 35:12
And they shall be unto you cities for refuge from the avenger; that the manslayer die not, until he stand before the congregation in judgment.
Hebrews 9:26
For then must he often have suffered since the foundation of the world: but now once in the end of the world hath he appeared to put away sin by the sacrifice of himself.