1 And awhen He had called His twelve disciples to Him, He gave them power over unclean spirits, to cast them out, and to heal all kinds of sickness and all kinds of disease.
2 Now the names of the twelve apostles are these: first, Simon, awho is called Peter, and Andrew his brother; James the son of Zebedee, and John his brother;
3 Philip and Bartholomew; Thomas and Matthew the tax collector; James the son of Alphaeus, and Lebbaeus, whose surname was Thaddaeus;
4aSimon the1 Cananite, and Judas bIscariot, who also betrayed Him.
Sending Out the Twelve
5 These twelve Jesus sent out and commanded them, saying: a“Do not go into the way of the Gentiles, and do not enter a city of bthe Samaritans.
Peter is the only one designated as the first. He is not only named first, he is called "the first" by Matthew, who was also an apostle—and an apostle ought to know who his human leader is.