'Three' in the Bible

Then Moses set apart three cities beyond the Jordan toward the sunrising;

At the end of every three years thou shalt bring forth all the tithe of thine increase in the same year, and shalt lay it up within thy gates:

Three times in a year shall all thy males appear before Jehovah thy God in the place which he shall choose: in the feast of unleavened bread, and in the feast of weeks, and in the feast of tabernacles; and they shall not appear before Jehovah empty:

At the mouth of two witnesses, or three witnesses, shall he that is to die be put to death; at the mouth of one witness he shall not be put to death.

thou shalt set apart three cities for thee in the midst of thy land, which Jehovah thy God giveth thee to possess it.

Thou shalt prepare thee the way, and divide the borders of thy land, which Jehovah thy God causeth thee to inherit, into three parts, that every manslayer may flee thither.

Wherefore I command thee, saying, Thou shalt set apart three cities for thee.

if thou shalt keep all this commandment to do it, which I command thee this day, to love Jehovah thy God, and to walk ever in his ways; then shalt thou add three cities more for thee, besides these three:

One witness shall not rise up against a man for any iniquity, or for any sin, in any sin that he sinneth: at the mouth of two witnesses, or at the mouth of three witnesses, shall a matter be established.