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 the wisest of men need to be on their guard against the efforts of the advocates of error.
For he hath greatly withstood our words - Margin, "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.

Of whom be thou ware also - It seems that this rabbin traveled about from place to place for the purpose of opposing the Gospel, the Jews putting him forward, as it is said, Acts 19:33.
He hath greatly withstood our words - Has been a constant opposer of the Christian doctrines.

Of whom be thou ware also,.... For he was now at Ephesus; and since he was such a malicious, ill natured, and troublesome person, as well as a blasphemer, an heretic, and had been delivered up to Satan, it was very advisable to shun his company, and have no conversation with him, and be upon the guard against him, that he might have no opportunity of doing hurt to him, or to the church at Ephesus:
for he hath greatly withstood our words: or doctrines; the truths of the Gospel preached by Paul and Timothy, which he opposed himself to, and resisted with all his might, and endeavoured to confute and overthrow; and wherein he was deficient in argument, he made up with railing and blasphemy; and this was the true reason of the apostle's imprecations on him, and why he would have Timothy beware of him, and avoid him, and not the personal injury he had done him.

our words--the arguments of us Christians for our common faith. Believers have a common cause.