It's not surprising that Douglass fills a speech on "The Church and Prejudice" with plenty of religious language and imagery. Douglass knows he needs to show how ridiculous it is for people who claim to follow Jesus to be prejudiced, so he juxtaposes all the symbols of Christianity with the prejudice that religion is guilty of.

Check out Douglass' second example of prejudice in the church:

But it seems, the kingdom of heaven is like a net; at least so it was according to the practice of these pious Christians; and when the net was drawn ashore, they had to set down and cull out the fish. Well, it happened now that some of the fish had rather black scales; so these were sorted out and packed by themselves. (8-9)

In the Gospels, Jesus begins many parables by saying, "The kingdom of heaven is like..." Douglass uses that familiar phrase to emphasize the gap between what Christianity should be like and what it is like.

Douglass also liberally peppers his speech with mentions of Christian symbols, as if to remind his listeners of the significance of these symbols within the religion they claim.

But among those who experienced religion at this time was a colored girl; she was baptized in the same water as the rest; so she thought she might sit at the Lord's table and partake of the same sacramental elements with the others. The deacon handed round the cup, and when he came to the black girl, he could not pass her, for there was the minister looking right at him, and as he was a kind of abolitionist, the deacon was rather afraid of giving him offense; so he handed the girl the cup, and she tasted. Now it so happened that next to her sat a young lady who had been converted at the same time, baptized in the same water, and put her trust in the same blessed Saviour; yet when the cup containing the precious blood which had been shed for all, came to her, she rose in disdain, and walked out of the church. (10-12)

The description of the symbols of communion within the text serve to remind listeners of their hypocrisy: they claim their religion is for all people, yet they treat some people as less worthy than others.