Isaacson brought together the large forces of the Oratorio Chorale, at full strength, and an expert chamber orchestra of players from the rosters of the Portland Symphony Orchestra and other groups. The choir was at the top of its game here. Without exception, its singing was solid, tight and texturally transparent, and whether Handel demanded vigor or introspection, the choir delivered it with admirable precision. And the orchestra, though playing modern instruments, produced a tight, focused sound that had the incisive edge of a period instrument group.