When reading a book I came upon a sentence, I can’t get the meaning of the sentence

As the shades of the night, were closing in, these expressions were supposed to embody this simple people’s views of the evening hymn. But it soon appeared that the song translation of ‘What we are going to receive’, &c.

Did they sing a hymn without knowing the meaning and the part about the translation, did they know the meaning later or was it for the readers to know. What is meant by ‘What we are going to receive’,&c.