Deuteronomy 19
8 Ref And if the Lord your God makes wide the limits of your land, as he said in his oath to your fathers, and gives you all the land which he undertook to give to your fathers;
9 Ref If you keep and do all these orders which I give you today, loving the Lord your God and walking ever in his ways; then let three more towns, in addition to these three, be marked out for you:
10 Ref So that in all your land, which the Lord your God is giving you for your heritage, no man may be wrongly put to death, for which you will be responsible.