'Three' in the Bible

Then Moses severed three cities on this side Jordan toward the sunrising;

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

Three times in a year shall all thy males appear before the LORD 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 the LORD empty:

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

Thou shalt separate three cities for thee in the midst of thy land, which the LORD thy God giveth thee to possess it.

Thou shalt prepare thee a way, and divide the coasts of thy land, which the LORD thy God giveth thee to inherit, into three parts, that every slayer may flee thither.

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

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:

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 the matter be established.