The hymne has in full 23 verses, It is an Abecedarius, meaning the first verse starts with the letter A, the second verse with B and so on.
Here is the text of the first two verses:
A solis ortus cardine
adusque terrae limitem
Christum canamus principem
natum Maria virgine.
Beatus auctor saeculi
servile corpus induit,
ut carne carnem liberans
non perderet, quod condidit.