In Mark 10:21, in the spiritual sense selling can be understood as rejecting the falsities which were the doctrine of the Jewish nation, and receiving the doctrine of truth from the Lord.

'To sell,' as in Revelation 8:17, signifies teaching doctrine.

'To sell,' as in Genesis 41:56, means transferring to another as their own, because what is sold becomes the property of the one who buys it.

(Reference: Arcana Coelestia 5371, Genesis 41; Mark 10)

5371. 'And sold to Egypt' means a making over to. This is clear from the meaning of 'selling' as making over to another as his own, for that which is sold becomes the property of the one who buys it. That 'selling' and 'buying' mean a making over to or a making one's own will be seen below in 5374.