It was announced after this episode aired that Damien (2016) would not be returning for a second season. This explains the slight cliffhanger nature of the final scenes.
The title of this final episode is a reference back to the 1976 original film. It is the name of the choral song featured in the movie which netted Jerry Goldsmith an Oscar nomination in the Best Song category.
The series ends like the original film, with Damien turning to the camera and smiling.