'Rear guard' in the Bible

The armed men went in front of the priests who blew the trumpets, and the rear guard came after the ark, while the priests continued to blow the trumpets.

The seven priests carrying the seven trumpets made of rams’ horns ahead of the ark of the Lord went on continually, blowing the trumpets; and the armed men went ahead of them and the rear guard came after the ark of the Lord, while the priests continued to blow the trumpets.