فَذَرْهُمْ فِى غَمْرَتِهِمْ حَتَّىٰ حِينٍ
Fazarhum fee ghamratihim hattaa heen
So leave them in their confusion for a time.
Ghamra comes from a root for water closing over a thing, so the sectarian pride described in the verse before is pictured as submersion rather than error. The term set is indefinite, a while with no length given, which leaves the instruction provisional. The command falls to the Messenger after the passage has said that the community was one, so what he withdraws from is a division that people made.