Someone told me that Paul may not have been the author of some of the Epistles of the NT. How do I approach them to disprove this claim?
There are some liberal approaches that claim Paul did not write many NT Epistles such as the Pastoral Epistles. However, it wasn’t until modern era that this changed. As a matter of fact, Pauline authorship was accepted universally until so called “historical-critical” methods introduced very humanistic methods of biblical study.
For instance, many scholars today question whether Paul could have written what’s in the Pastoral Epistles. They say Paul’s disciples patched together pieces of his correspondence, and then inserted their own material to make up the rest of these letters. So we must begin today with some people by clearing away doubts about reliability. We can start with the fact that letters written in the ancient world always carried the name of the sender. Paul’s name appears exactly in that place. As a matter of fact, no Greek manuscripts exist that do not give Paul’s name as author!
It gets even worse for those who deny Pauline authorship. Liberal critics of Pauline authorship even disagree among themselves which verses and parts of these letters are from Paul, and which were inserted by his disciples. That means their collective analysis shows they admit that Paul could have written all these things.
But does it really matter who wrote them? Absolutely. The major reason Pauline authorship is dismissed is because of their pointed doctrinal teachings which, if they can deny Paul wrote, allows these teachings to be marginalized and explained away. So the importance of this question isn’t merely an academic one.
Even the local and personal references fit in with the assumption Paul was freed from his Roman imprisonment at the end of Acts just as he anticipated. The attempt to fit the geographical and historical references of Paul’s journeys into Acts (9-28) is really an impossible task. It is much more likely these Pastoral letters were from a later period than Acts. We know that Paul did visit the western Mediterranean as he had planned. This fits because at that time he was only a house-prisoner in Rome who expected to be released. This is further supported by some early writings that say this occurred (see 1 Clement).
So, both historical sources and the clear manuscript evidence are in support of Paul being the author of these Epistles. Some objections could be raised on literary grounds but any good conservative commentary demonstrates the weaknesses of these spurious arguments. To dismiss Paul as author is because of a theological bias, not because of the weight of the testimony of history or available manuscript evidence. That’s willful delusion, not facts.