This a song by Loreena McKennit. The music really touched me, so i read the lyrics. And the lyrics are equally moving.
"The two trees" is a poem by William Butler Yeats (1865-1939), the music is by Loreena McKennitt.

Loreena McKennitt - Cé hé mise le unlaight? / The two trees

Beloved, gaze in thine own heart,
The holy tree is growing there;
From joy the holy branches start,
And al the trembling flowers they bear.
The changing colours of its fruit
Have dowered the stars with merry light;
The surety of its hidden root
Has planted quiet in the night;
The shaking of its leafy head
Has given the waves their melody,
And made my lips and music wed,
Murmuring a wizard song for thee.

There the Loves a circle go,
The flaming circle of our days,
Gyring, spiring to and fro
In those great ignorant leafy ways;
Remembering all that shaken hair
And how the winged sandals dart,
Thine eyes grow full of tender care;
Beloved, gaze in thine own heart.

Gaze no more in the bitter glass
The demons, with their subtle guile,
Lift up before us when they pass,
Or only gaze a little while;
For there a fatal image grows
That the stormy night receives,
Roots half hidden under snows,
Broken boughs and blackened leaves.
For all things turn to barenness
In the dim glass the demons hold,
The glass of outer weariness,
Made when God slept in times of old.
There, through the broken branches, go
The ravens of unresting thought;
Flying, crying, to and fro,
Cruel claw and hungry throat,
Or else they stand and stiff the wind,
And shake their ragged wings: alas!
Thy tender eyes grow all unkind:
Gaze no more in the bitter glass.

Beloved, gaze in thine own heart
The holy tree is growing there;
From joy the holy branches start,
And all the trembling flowers they bear.
Remembering all that shaken hair
And how the winged sandals dart,
Thine eyes grow full of tender care:
Beloved, gaze in thine own heart.