Wat mean precedence in law term?

Question

BAIRAVI.A FROM SELANGOR.

Answer 1

When a judge issues a decision, other judges in future similar cases can use it a basis for their decision. This called "setting precedent."

Answer 2

Precedence means that there was a court ruling in the law books of a previous case with similar issues, that preceded the current case being ruled.  (i.e., that it has a legal basis going back to the Constitution), and is therefore a solid basis for future rulings.  

Some cases said to be without precedent are U.S.Supreme Court rulings that excluded prayer from schools, or even silent prayer.   Since our nation's founders considered teaching the Bible essential to the health of our democracy, including chaplains and opening prayer for our Congress, and for the Supreme Court itself, then this is clearly an arbitrary ruling, to remove prayer and the Bible from our schools, and without precedent in previous history of U.S. law.  

Especially infuriating is when they look at European law for guidance, with greater weight than they look at the Constitution.