Theorema de sacramentorum nucleo

ones, two or three, or Uniones singular pearls, so called because the shells of that land bear a few at a time, but they are larger.
In the time of the Church's free divine benevolence, as soon as the heart is purified by faith, the Pearl of the Gospel is not indeed born in us, but it regenerates us, so that we are reborn not from mortal seed, but from immortal seed, through the word of the living God. Let us learn to maintain good works for necessary uses, so that we may not be unfruitful (1 Peter 1:23; Titus 3:14).

Shells, says Pliny, when the generative hour of the year stimulates them, opening themselves with a certain yawning, are said to be filled with dew, and afterward they become pregnant and bring forth pearls, according to the quality of the dew received. If pure dew flows in, the whiteness is seen; but if it is turbid, the offspring also becomes sullied.

The Gospel, if Christ is announced purely with a willing heart, is more illustrious; but if Christ is preached with προσάσει additions/corruptions, it is more obscure and less pure and sincere.

But just as pearls, although they are born in the sea, nevertheless have a kinship with the sky, as Pliny shows in these words when he adds that the whiteness of pearls pales when the sky threatens rain; from this it is evident that they have a greater association with the sky than with the sea, and from there they take a cloudy color or, in accordance with the morning clarity, a serene one.

Thus, minds imbued and illustrated by the doctrine of the Gospel are joined to heaven, not fixed to the earth. They seek things above, where Christ is, sitting at the right hand of God. They care for heavenly things, not earthly ones (Colossians 3:1-2).

Pliny says of shells: If they are sated in time, they grow large and produce. Thus, when the Gospel is announced in time, the Saints grow in all things toward him who is the head, namely Christ (Ephesians 4:15). They walk as is worthy of the Lord, so that they may please him in all things, bearing fruit in every good work and growing in the knowledge of God (Colossians 1:10).

Pliny writes: If it thunders, the shells are compressed and, according to the manner of fasting, they are diminished. But if it also thunders, fearful and suddenly compressed, they make what they call φυσήματα puffings/wind-bubbles, but puffed up with emptiness, without body; these are the abortions of the shells.