'Scarlet,' as in Genesis 38:28, signifies spiritual good.

In Isaiah 1:18, this signifies truth derived from good, or truth from a celestial origin, such as is the truth of the Word in its literal and natural sense

'Scarlet,' in Revelation 17:3, signifies truth from a heavenly origin, such as is the truth of the Word in the sense of the letter or natural sense, which is meant by what is holy in it. 

(Referenser: Apocalypse Explained 67)

3190. 'And they rode on the camels' means the understanding part of the mind, raised up above natural facts. This is clear from the meaning of 'riding' as the understanding when raised up, dealt with in 2761, 2762, and from the meaning of 'camels' as general facts in the natural man, dealt with in 3048, 3071, and so natural facts. The implications of this are that when truth from the natural is raised up into the rational it is borne out of the sphere of worldly light into that of heavenly light - so to speak from the obscurity of night into the brightness of day. For the things that belong to the light of the world, in which all natural objects exist, dwell so to speak in night, compared with things belonging to the light of heaven; but things that belong to the light of heaven, in which all spiritual objects exist, dwell so to speak in daylight, compared with things belonging to the light of the world. Consequently when truth from the natural is raised up towards the rational, the person is raised up at the same time into intelligence and wisdom. All the intelligence and wisdom present with man comes from this source. These are the things meant by the understanding part, raised up above natural facts.