Dayyan derives from the root din (to judge, to plead a cause). It appears in 1 Samuel 24:15 where David calls God his dayyan — his ultimate judge between himself and Saul. The term is intensified from the simple judge to the one who definitively settles matters. In Jewish tradition, dayyan became the title for a rabbinic court judge in halachic matters.
David's appeal to God as dayyan reflects deep theological confidence: when human courts fail, when the powerful abuse the weak, the ultimate Judge is watching. The doctrine of divine judgment is not primarily about condemnation — it is about vindication. God as Judge means the oppressed will not be forgotten, the truth will not be buried, and every account will be settled. 'Shall not the Judge of all the earth do what is just?' (Genesis 18:25).