Charles Ellicott Commentary Numbers 35:10-11

"Speak unto the children of Israel, and say unto them, When ye pass over the Jordan into the land of Canaan, then ye shall appoint you cities to be cities of refuge for you, that the manslayer that killeth any person unwittingly may flee thither." — Numbers 35:10-11 (ASV)

When you have come over Jordan ... — Or, You are going over the Jordan into the land of Canaan; and you shall appoint ...