From Charles Sumner's argument in Sarah C. Roberts vs. the City of Boston

It is easy to see that the exclusion of colored children from the Public Schools is a constant inconvenience to them and their parents, which white children and white parents are not obliged to bear. Here the facts are plain and unanswerable, showing a palpable violation of Equality. The black and white are not equal before the law. I am at a loss to understand how anybody can assert that they are….

… this consideration cannot be neglected, the matters taught in the two schools may be precisely the same; but a school exclusively devoted to one class, must differ essentially in spirit and character from that Common School known to the law, where all classes meet together in Equality. It is a mockery to call it an equivalent.

… [Black children] have an equal right with white children to the Common Schools. A separate school, though well endowed, would not secure to them that precise Equality which they would enjoy in the Common Schools…Thus much for the doctrine of equivalents as a substitute for equality….

… The whole system of Common Schools suffers also… The law contemplates not only that all shall be taught, but that all shall be taught together. They are not only to receive equal quantities of knowledge, but all are to receive it in the same way. All are to approach the same common fountain together; nor can there be any exclusive source for any individual or any class. The school is the little world where the child is trained for the larger world of life…And since, according to our institutions, all classes, without distinction of color, meet in the performance of civil duties, so should they all, without distinction of color, meet in the school — beginning there those relations of Equality which Constitution and Laws promise to all.

Equality before the law, unconstitutionality of separate colored schools in Massachusetts: argument of Charles Sumner, Esq., before the Supreme Court of Massachusetts, in the case of Sarah C. Roberts vs. the city of Boston, December 4, 1849, F. & J. Rives & Geo. A. Bailey, Reporters and Printers of the debates of Congress, 1870.