These are the lyrics quoted by Helen above (but still not the ones the original poster wanted). I found them at a website called song-archive.livejournal.com. Attribution is also copied from there:


DAVID OF THE WHITE ROCK / DAFYDD Y GARREG WEN
Melody: anon./trad. / David Owen (1712-1741)
Lyrics: Ceiriog Hughes (1832-1887)
Origin: Welsh


Bring me, said David, the harp I adore;
I long, ere death calls me, to play it once more.
Help me to reach my belov'd strings again;
On widow and children, God's blessing remain.

Last night I heard a kind angel thus say,
"David fly home on the wings of thy lay".
Harp of my youth, and thy music, adieu;
Widow and children, God's blessing on you.


'Cariwch,' medd Dafydd, 'fy nhelyn i mi,
Ceisiaf cyn marw roi tôn arni hi.
Codwch fy nwylo i gyrraedd y tant
Duw a'ch bendithio, fy ngweddw a'm plant.'

'Neithiwr mi glywais lais angel fel hyn,
"Dafydd, tyrd adref a chwarae trwy'r glyn,"
Delyn fy mebyd, ffarwel i dy dant,
Duw a'ch bendithio, fy ngweddw a'm plant.