These are the words I remember from 50 years ago. They go to the melody linked above.

Hark now, o shepherds, great tidings we bring.
Mighty the Monarch whose praises we sing.
O'er all the world a star brightly beaming
soft sheds its loving rays, gently streaming.
Shepherds, rejoice!

Angels, bright shining, [great tidings you bring].
News of sweet Mary and Jesus our king.
Straight shall we journey, forth gladly bringing
all our devotion, fervently singing alleluia.

See now in beauty sweet mother and child.
God's tender light o'er them, glowing and mild.
There in the manger lies Jesus holy,
son of the Virgin, Mary the lowly.
Glory to God!

Then followed a fancy Alleluia part, ending with a low 'Glory to God' by the second altos.

I'm not completely sure that the part in [] is right.