זוהר שמות — דף רנז ע”ב

The Sanhedrin had to open capital judgments with merit to include grace in the judgment. Isaac and Rebecca are united - one is judgment and the other is merit - so that completeness is one. On Rosh Hashanah, merit and judgment must be united so that sin does not prevail. When the other side dominates, there is no completeness but accusation and the four capital punishments. The prophets support the oral Torah between the two sides, nogah and zohar.