604. 13:16 And it causes all, both small and great, rich and poor, free and slave. This symbolizes all the people in the Protestant Reformed church, of whatever condition, degree of education, or degree of intelligence.

The small and great here mean people of a lesser or greater degree of status, thus of whatever condition. The rich and poor mean people of more or less knowledge and learning (no. 206), thus of whatever degree of education. Free and slave mean people who acquire wisdom on their own or who gain it from others (no. 337), thus of whatever degree of intelligence.

So then, small and great, rich and poor, free and slave, mean all the people in the Protestant Reformed church of whatever condition, degree of education, or degree of intelligence. This is the meaning in the spiritual sense.