Arcana Coelestia#9645
9645. 'Two bases under one board' means the joining of it to the good. This is clear from the meaning of 'two' as a joining together, dealt with in 5194, 8423; from the meaning of 'bases' as truth through which support is received, dealt with in 9643; and from the meaning of 'board' as good that lends support, as immediately above in 9644.
Arcana Coelestia#9644
9644. 'Under the twenty boards' means which proceeds from the good that comes from the Lord's Divine Human. This is clear from the meaning of 'twenty' as that which is complete, thus in every respect and totally, dealt with above in 9641; and from the meaning of 'the boards of the dwelling-place' as the good lending support to heaven, dealt with in 9634. This good is the good of merit, and so belongs to the Lord's Divine Human, see 7850, 9127; and it is the one and only good that reigns in heaven, 9486. The fact that the truth meant by 'the bases' proceeds from this good is meant by the presence of the bases 'under the boards'.