MUSIC / The word made flesh: Edward Seckerson reports on the opening concert of the 1994 Edinburgh Festival

A mighty organ chord, a huge intake of breath, and the massed voices descend with their summons: 'Veni, Creator Spiritus'. Critics of Mahler's Eighth Symphony may ask: 'Yes, but when? When does he come?' But for an international festival director with probably the best amateur chorus in the world at his bidding, the answer is an unequivocal 'soon'.

And on Sunday, in Edinburgh, the spirit did come, did move. The Usher Hall organ still silently awaits restoration, so it fell to an electronic impostor to throw down the first chord of the festival: E flat major. But it was E for exaltation as soon as Arthur Oldham's splendid Edinburgh Festival Chorus made flesh of the word. Forget 'Symphony of a Thousand', two or three hundred will do nicely, thank you. A lean, hungry chorus of this quality can put the 'impetuoso' back into Mahler's allegro impetuoso. Rhythm once again drove the unstoppable march of his 'Creator Spiritus' setting: it was good to hear the challenging Beethovenian double fugue at its heart so bravely and incisively negotiated. No woolly under-the-note sopranos, no flaccid tenors. When this chorus hurls out the words 'Accende lumen sensibus' ('Inflame our senses with light'), you wonder why they need to ask.

But is Mahler's Eighth really much more than a grand 'occasion'? Does it really work, this choral symphony cum oratorio cum opera, this curious meeting of the religious and the humanistic? Can we ever really believe in Mahler, the optimist (or is it hopeful pessimist?), offering redemption for all, through faith, through love? That rather depends on who is at the helm.

A wise conductor will not resist, or underplay, the purple, star-spangled sanctimony of Part 2 - where Mahler meets Goethe meets the angels - but rather surrender wholeheartedly to the innocence of the vision. This is Mahler, the mystic, in Wunderhorn wonderland. You either believe or leave. Donald Runnicles believes; or else he's a master of deception. He was right inside the style here, catching the opening invocation on the wing, prepared to risk security (one or two moments fleetingly out of phase, quickly recovered) for inspirational heat. His commanding technique makes light work of Mahlerian tempo rubato. It's never enough merely to observe the monumental stresses, the protracted ritardandi: either they're a part of your central nervous system or they're nothing at all. The Royal Scottish National Orchestra responded with ripe and confident playing. Runnicles duly stretched the credibility of their violins as the 'Mater Gloriosa' glided by on a cushion of harps and harmonium, and our ascent to still higher regions was unashamedly indebted to the Sugar Plum Fairy, rippling celesta and piano in attendance.

But this is primarily a symphony for voices, and Runnicles' eight soloists were well integrated into the choral fabric, if all but sabotaged by a lamentable tenor, Peter Svensson, whose card was marked for disaster right from the start of his strained and appallingly ill-tuned contributions to Part 1. Of the excellent women, the mezzos Catherine Keen and Patricia Bardon displayed real vocal presence, while sopranos Janice Watson and Jane Eaglen - stars, both - entwined gloriously in the final ascendancy of the 'Chorus Mysticus'. That grew from a barely discernable hum to a full-throated paean with trumpets from the rear of the hall recalling the 'Veni, Creator' theme, its interval of a seventh now stretching beyond the octave towards spheres unknown. Suddenly you're thinking: O ye of little faith.