They contained the proofs and promises of that religious faith in God and hope of heaven, for the sake of which they suffered such things.

Is it credible that they would allow them to be altered and corrupted?
You might far more rationally talk of altering the Declaration of Independence, or the Constitution of the United States.

Translated into different languages--transported into Britain, Germany, France, Spain, Italy, Greece, Turkey, Carthage, Egypt, Parthia, Persia, India, and China--committed to memory by children, and quoted in the writings of Christian authors of the first three centuries, to such an extent, that we can gather the whole of the New Testament, except twenty-six verses, from their writings--appealed to as authority by heretics and orthodox in controversy--and publicly read in the hearing of tens of hundreds of thousands every Sabbath day in worship--we are a thousand times more certain that the New Testament has not been corrupted, than we are that the Declaration of Independence is genuine.
On this ground then we plant ourselves.

The whole story of a late and gradual formation of the New Testament, or, in plain English, of its forgery, stands out as an unmitigated falsehood in the eyes of every man capable of writing his own name.

The first churches could not be deceived with forgeries for apostolic writings.