'Three' in the Bible

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

At the end of every three years you shall bring forth all the tithe of your increase in the same year, and shall lay it up within your gates:

Three times in a year shall all your males appear before Yahweh your 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 tents; and they shall not appear before Yahweh empty:

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

you shall set apart three cities for you in the midst of your land, which Yahweh your God gives you to possess it.

You shall prepare you the way, and divide the borders of your land, which Yahweh your God causes you to inherit, into three parts, that every manslayer may flee there.

Therefore I command you, saying, You shall set apart three cities for yourselves.

if you keep all this commandment to do it, which I command you this day, to love Yahweh your God, and to walk ever in his ways; then you shall add three cities more for yourselves, besides these three:

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