Nicene and Post-Nicene Fathers: Series I/Volume IV/Donatist Controversy/Answer to the Letters of Petilian, the Donatist/Book II/Chapter 24
Chapter 24.—56. Petilianus said: "But you will answer that you abide by the same declaration, ‘He that is once washed needeth not save to wash his feet.’[1] Now the ‘once’ is once that has authority, once that is confirmed by the truth."
57. Augustin answered: Baptism in the name of the Father and of the Son and of the Holy Ghost[2] has Christ for its authority, not any man, whoever he may be; and Christ is the truth, not any man.