Adam Clarke on 2 Timothy 4:14

Alexander the coppersmith - We are not to understand this of any tradesman, but of some rabbin; for it was not unusual for the Jews to apply the name of some trade as an epithet to their rabbins and literary men. He is, in all probability, the very same mentioned Act 19:33 (note); and it is not unlikely that he may have been the same whom the apostle was obliged to excommunicate, 1Tim 1:20.

The Lord reward him - Αποδῳη αυτῳ ὁ Κυριος· But instead of αποδῳη, which has here the power of a solemn imprecation, αποδωσει, he will reward, is the reading of the very best MSS., several of the versions, and some of the chief Greek fathers. This makes the sentence declaratory: The Lord Will reward him according to his works. This reading is most like the spirit and temper of this heavenly man. See 2Tim 4:16.