When 'islands' are contrasted to 'earth' or 'mountains,' they signify the truths of faith, because they are in the sea. They signify doctrinal things which are rituals. 'Islands' signify peoples who are more remote from the worship of God. People who are steeped in the internal sense of the Word, such as angels, do not know what islands are, because they no longer have any concept of such places. Instead they have a perception of more remote worship, like the gentiles outside the church.

'Islands,' in Ezekiel 27:6, signify people in the church in a natural, materially-oriented state but still rational.

(Verweise: Apocalypse Explained 406; Isaiah 1, Isaiah 49, 49:1)

The internal meaning of “blood” is a little tricky. In most cases, blood is linked with Divine Truth and it’s relationship with the Lord. But in some cases, especially when discussing the first half of Genesis, the Works of Swedenborg link blood to a state of caring, or love to the neighbor. No absolute explanation is offered for this, but it’s worth noting that blood takes a number of forms in the body – it sometimes carries nutrients and oxygen, sometimes waste products, and sometimes nutrients and carbon dioxide. So it’s not unreasonable for blood to have different meanings in different contexts.