[Since the nineteenth century] the attribution of these letters to Paul has been questioned.
Most scholars are convinced that Paul could not have been responsible for the vocabulary and style, the concept of church organization, or the theological expressions found in these letters.
A second group believes, on the basis of statistical evidence, that the vocabulary and style are Pauline, even if at first sight the contrary seems to be the case…
Other scholars…suggest that the apostle made use of a secretary who was responsible for the composition of the letters.
A fourth group of scholars believes that these letters are the work of a compiler…
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…In spite of these problems of authorship and dating, the Pastorals are illustrative of early Christian life and remain an important element of canonical scripture.
NABRE