Brethren in Genesis 27:29 signify the affections of good.

(References: Arcana Coelestia 3582)

3582. 'Be lord over your brothers' means the apparent dominion at first of the affection for natural truth over affections for natural good. This is clear from the meaning of 'being lord over' as having dominion, and from the meaning of 'brothers' as affections for good, in this case natural good, dealt with in 367, 2360, 3303. Regarding the apparent dominion at first of truth over good, see 3324, 3325, 3330, 3332, 3336, 3470, 3539, 3548, 3556, 3563, 3570.