Albert Barnes Commentary Matthew 10:3

"Philip, and Bartholomew; Thomas, and Matthew the publican; James the [son] of Alphaeus, and Thaddaeus;" — Matthew 10:3 (ASV)

Lebbaeus, whose surname was Thaddeus. These two words have the same meaning in Hebrew. Luke calls him Judas, by a slight change from the name Thaddaeus. Such changes are common in all writings.