Had I the music of heaven and earth, With its changing tempo of winds and seasons, And the lilting chorus of singing birds, And the endless chant of waters moving Under the lisping leaves of the spring, I would praise you, dearest, with many voices; But, having no gift of an angel's tongue, I play on the muted strings of my heart With the heavy bow of the sky's loud silence, And the depthless passion of quiet seas.
Fugue begins with a long, wistful "if." The speaker imagines having all the music of the world at hand: the shifting rhythm of the seasons, birdsong, the steady murmur of water under spring leaves. With a gift like that, he says, he could praise his beloved in many voices at once. But he doesn't have an angel's tongue, so he turns inward instead.
What he does offer is a quieter kind of music, played on the "muted strings" of his heart. The ending is a nice paradox: the bow is "heavy," the silence is "loud," the passion is "depthless" yet quiet. He seems to be saying that his love is too big and too still for words or showy sound, and that its silence is itself the expression.
The mood is tender, humble, and hushed. The title fits too, since a fugue weaves many voices together, much like the "many voices" the speaker longs for but replaces with a single, deep one.