‘And the shepherds returned, glorifying and praising God for all the things that they had heard and seen, even as it was spoken to them.'
And as for the shepherds, they returned to the countryside, and to their flocks, glorifying and praising God for all that they had heard and seen. Such behaviour inevitably follows reception of the Good News. Compare Luke 5:26; Luke 7:16; Luke 13:13; Luke 17:15; Luke 18:43; Luke 23:47; Acts 2:47; Acts 4:21; Acts 10:46; Acts 13:48. The glad tidings were for all mankind.
Note the interesting contrasts. The hearers were filled with wonder, Mary kept it all in her heart and meditated on it, the shepherds glorified and praised God. They had no doubt about what had happened.