In Psalm 84:3, 'a sparrow' signifies spiritual truth, and 'a swallow' signifies natural truth from which worship is performed.

(Odkazy: Apocalypse Explained 391)

'Being sent' means coming forth, (or going forth), in the internal sense, as in John 17:8. In similar manner, it is said of the holy of the spirit, that it was 'sent,' that is, it goes forth from the divine of the Lord, as in John 15:26, 16:5, 7.

So, too, the prophets were called 'the sent,' because the words which they spoke went forth from the holy of the spirit of the Lord.

'To be sent,' as in Genesis 37:13, signifies teaching.

(Odkazy: Arcana Coelestia 2397; John 15:7)