The unnamed tune by Lundy has a time-signature of 2/2 and was in the key of C#m in the the original version with the first few notes being G B c c.
It is still included in the 2008 edition of Catholic Hymns Old and New - purchasing this book is the best way to get sheet-music for it.
Small choir with organ (this hymn starts just after 4:00)
LyricsThe lyrics are copyright so cannot be reproduced here. But they are currently available on this website (page 4).
The song starts with a two-line chorus, and this is repeated after each of the five verses. A rough outline is:
O my people, what have I done to you?
How have I hurt you? Answer me.
1 I led you out of Egypt.
... You have prepared a cross for me.
2 I led you as a shepherd;
... You have ...
3 I fought for you in battles,
.. You have ...
4 I planted you, my vineyard,
... Only the cross you made for me.
5 Then listen to my pleading
... For you I suffer bitterly.