Albert Barnes Commentary 2 Timothy 4:15

"of whom do thou also beware; for he greatly withstood our words." — 2 Timothy 4:15 (ASV)

Of whom be thou ware also. It would seem from this, that Alexander was still a public teacher, and that his discourses were plausible and artful. The best and wisest of men need to be on their guard against the efforts of the advocates of error.

For he hath greatly withstood our words. The marginal note says, preachings. The Greek is, words; but the reference is, doubtless, to the public teachings of Paul. This verse makes it clear that it was no private wrong that Paul referred to, but the injury which he was doing to the cause of truth as a professed public teacher.