"As one who has slept"

People keep pointing out to me these wonderful hymns that I don't know!

This one is - as usual, I find, with John Tavener - just stunningly beautiful:

From the Liturgy for Great and Holy Saturday:

"As one who has slept the Lord has risen
And rising he has saved us. Alleluia."

Music by Sir John Tavener; The Choir/James Whitbourne, conductor