Deuteronomy 19:9 in the World English Bible
and if you keep all this commandment to do it, which I command you today, to love the LORD your God, and to walk ever in his ways, then you shall add three cities more for yourselves, in addition to these three.
Context
8 And if the LORD thy God enlarge thy coast, as he hath sworn unto thy fathers, and give thee all the land which he promised to give unto thy fathers;
9 If thou shalt keep all these commandments to do them, which I command thee this day, to love the LORD thy God, and to walk ever in his ways; then shalt thou add three cities more for thee, beside these three:
10 That innocent blood be not shed in thy land, which the LORD thy God giveth thee for an inheritance, and so blood be upon thee.