Belly
The belly, in Psalms 16:4, signifies the interior understanding.
In Genesis 25:23, it signifies conception of interior and exterior good. (Arcana Coelestia 3293)
In Isaiah 46:3, the belly signifies from the beginning of the church. (Arcana Coelestia 4918[2], 5550)
The belly signifies people who are being regenerated, and people who have been regenerated. (Apocalypse Explained 710[3])
(References: Apocalypse Explained 622)
John 7:37-39
37
Now on the last and greatest day of the feast, Jesus stood and cried out, "If anyone is thirsty, let him come to me and drink!
38
He who believes in me, as the Scripture has said, from within him will flow rivers of living water."
39
But he said this about the Spirit, which those believing in him were to receive. For the Holy Spirit was not yet given, because Jesus wasn't yet glorified.