Joshua 23:6

Be ye therefore very courageous For it would require great courage and resolution to execute all the commands of Moses, and particularly that of expelling and destroying the residue of the Canaanites. The right hand or the left That is, in one kind or other, by adding to the law, or diminishing from it. Which was the condition upon which God promised to continue them in the possession of the land. By this it is evident that the book of the law of Moses was extant in those days, and that the people read it.