Good post here by Hope’s Reason
Many New Testament scholars would deny that Paul wrote 1-2 Timothy or Titus. I accept the Pauline authorship, but not just because I am an Evangelical.
There is no doubt that there are differences between the pastoral epistles and the “authentic” epistles. It is good for us to notice these differences and we should be looking for the reason for those differences. What are the main reasons for denying Pauline authorship? There is a difference in style and there is what is seen as too highly organized of a church with bishops and deacons.
First let me deal with they style. What one should first note is that the “authentic” epistles are the earliest of Paul’s letters, while the pastorals are the last letters he wrote. I think it is reasonable to consider that there may be some changes in style and vocabulary over the years. In addition, these letters were written close to Paul’s death, with 2 Timothy including an anticipation of an impending execution. I can see that as affecting style. Finally, these letters were not written to churches but to pastors that Paul had been mentoring. This would lead to differences, not just to a letter like Romans, but a personal letter such as Philemon. We all write differently based on who our audience is. My emails to a church would look very different from my emails to a close friend, including differences in vocabulary.