916. [verse 21] 'And the twelve gates were twelve pearls, and each one of the gates was of one pearl' signifies that the acknowledgment and cognition of the Lord conjoins into one all the cognitions of truth and good that are derived from the Word, and introduces into the Church. By 'the twelve gates' are signified in a summary the cognitions of truth and good by which a man is introduced into the Church (n. 899, 900). By the 'twelve pearls' are also signified cognitions of truth and good in a summary (n. 727). This is why the gates were pearls. The reason why 'each one of the gates was of one pearl' is because all the cognitions of truth and good that are signified by' the gates' and 'the pearls' relate to one cognition which is holding them together, and this one cognition' is the cognition of the Lord. It is said 'one cognition', although there are many cognitions making up that one cognition'; for the cognition of the Lord is the universal of all the things of the doctrine and consequently of all the things of the Church. All worship draws its life and soul therefrom, for the Lord is everything in all the things of heaven and the Church, and consequently in all the things of worship.  The reason why the acknowledgment and cognition of the Lord conjoins all the cognitions of truth and good derived from the Word into one is because there is a connection of all spiritual truths (veritas), and, if you are willing to believe it, their connection is like the connection of all the members, viscera and organs of the body. And therefore just as the soul holds together all those things in their order and connection, so that they are not felt otherwise than as one, in like manner the Lord holds together all the spiritual truths (veritas) with a man. That the Lord is the very Gate by which entry should be made into the Church and thereby into heaven, He Himself teaches in John:-
I am the Door, by Me if anyone enters in, he shall be saved John x 9.
And that the acknowledgment and cognition of Himself is the 'pearl' itself is understood by these words of the Lord in Matthew:-
The kingdom of the heavens is like unto a merchant man seeking beautiful pearls who, when he had found one pearl of great value, went and sold all that he had and bought it Matt. xiii 45, 46;
the 'one pearl of great value' being the acknowledgment and cognition of the Lord.