In 1854 John Thomas was a member of a church in New York known as the Royal Association of Believers. In that year he published the Constitution of the Association in his magazine, The Herald of the Kingdom and the Age to Come.
The Constitution included these clauses on membership and "the Lord's table":
4. WH0 ARE INVITED TO MEMBERSHIP.
"The wisdom from above being first pure, and then peaceable, gentle, easy to be entreated, full of mercy and good fruits, without partiality and without hypocrisy" - we cordially invite all immersed believers of the gospel preached to Abraham, Israel, and the Gentiles, by the Angel of Jehovah, Moses, Jesus, and the apostles, who are disposed to illustrate this "wisdom from above" in word and deed, to unite with the undersigned for the purposes set forth in No. 3.
5. WHO HAVE THE PRIVILEGE OF CHRISTIAN WORSHIP WITHOUT MEMBERSHIP.
Being the Lord's table, and not the table of the Association, all of good report within the city or without it, who, believing the gospel of the kingdom, have been immersed, are cordially invited to worship with us; the only privileges withheld being a participation in the direction of our affairs, and speech without previous invitation.
We should first note the distinction that is made between membership of the association, and fellowship at the Lord's table. Any association has the prerogative to make rules about its own membership, but John Thomas and his fellow-elders in the Association of Believers rightly recognised that they did not have a prerogative to exclude good Christian men and women from the Lord's table.
In this respect the earliest Christadelphian practices were in line with our Lord's teachings and His table-fellowship practice of inclusiveness.