Herod: That is, Herod Agrippa I, grandson of Herod the Great. (See Glossary.) Born in 10 B.C.E., Herod Agrippa I was educated in Rome. He cultivated friendships with various members of the imperial family. One friend was Gaius, better known as Caligula, who became emperor in 37 C.E. He soon proclaimed Agrippa king over the regions of Ituraea, Trachonitis, and Abilene. Later, Caligula expanded Agrippa’s domain to include Galilee and Perea. Agrippa was in Rome when Caligula was assassinated in 41 C.E. Reportedly, Agrippa played an important role in resolving the crisis that ensued. He participated in tense negotiations between another powerful friend, Claudius, and the Roman Senate. The result was that Claudius was proclaimed emperor and civil war was averted. To reward Agrippa for his mediation, Claudius granted him kingship also over Judea and Samaria, which had been administered by Roman procurators since 6 C.E. Thus Agrippa came to be in charge of territories equaling those of Herod the Great. Agrippa’s capital was Jerusalem, where he won the favor of the religious leaders. He is said to have observed Jewish law and traditions scrupulously by, among other things, offering sacrifices in the temple daily and reading the Law publicly. He is also said to have been a zealous protector of the Jewish faith. However, he belied his claim of being a worshipper of God by arranging gladiatorial combats and pagan spectacles in the theater. Agrippa’s character has been described as treacherous, superficial, and extravagant. His rule was cut short when he was executed by Jehovah’s angel, as described at Ac 12:23. Scholars place the death of King Herod Agrippa I in 44 C.E. He was at that time 54 years old and had reigned for three years over all Judea.

put James the brother of John to death: The execution probably took place about the year 44 C.E. James thus became the first of the 12 apostles to die as a martyr. Herod may have targeted James because that apostle was known to be particularly close to Jesus or because James had a reputation for fiery zeal. It was likely for this reason that James and his brother John had been given the surname Boanerges, which means “Sons of Thunder.” (Mr 3:17) Herod’s cowardly, politically motivated act did not stop the spread of the good news, but it did rob the congregation of a beloved apostle, shepherd, and source of encouragement. The expression by the sword may indicate that James was beheaded.

the days of the Unleavened Bread: The Festival of Unleavened Bread began on Nisan 15, the day after the Passover (Nisan 14), and lasted for seven days. (See Glossary, “Festival of Unleavened Bread,” and App. B15.) The frequent references in the Gospel accounts and the book of Acts to the various festival seasons show that the Jewish calendar continued to be observed by the Jews during the time of Jesus and the apostles. These festival seasons serve as a guide for determining the approximate time of Biblical events of that time.​—Mt 26:2; Mr 14:1; Lu 22:1; Joh 2:13, 23; 5:1; 6:4; 7:2, 37; 10:22; 11:55; Ac 2:1; 12:3, 4; 20:6, 16; 27:9.

Jehovah’s angel: See study note on Ac 5:19 and App. C3 introduction; Ac 12:7.

Get dressed: Or “Gird yourself.” Apparently referring to securing a loose inner garment with a belt or a piece of cloth.​—See study note on Lu 12:35.

Jehovah sent his angel: The phrase “sent his angel” calls to mind similar acts of deliverance mentioned in the Hebrew Scriptures. For example, at Da 3:28; 6:22, God is said to have “sent his angel” to rescue Daniel and his companions.​—Compare Ps 34:7; see App. C3 introduction; Ac 12:11.

Mark: From the Latin name Marcus. Mark was the Roman surname of the “John” mentioned at Ac 12:12. His mother was Mary, an early disciple who lived in Jerusalem. John Mark was “the cousin of Barnabas” (Col 4:10), with whom he traveled. Mark also traveled with Paul and other early Christian missionaries. (Ac 12:25; 13:5, 13; 2Ti 4:11) Although the Gospel nowhere specifies who wrote it, writers of the second and third centuries C.E. ascribe this Gospel to Mark.

the house of Mary: The congregation in Jerusalem apparently met in a private home, that of Mary the mother of John Mark. The house was spacious enough to accommodate “quite a few” worshippers, and a servant girl worked there. So Mary may have been a relatively wealthy woman. (Ac 12:13) Further, the residence is referred to as “the house of Mary,” without any mention of a husband, so it is possible that she was a widow.

John who was called Mark: One of Jesus’ disciples, “the cousin of Barnabas” (Col 4:10), and the writer of the Gospel of Mark. (See study note on Mr Title.) The English name John is the equivalent of the Hebrew name Jehohanan or Johanan, which means “Jehovah Has Shown Favor; Jehovah Has Been Gracious.” At Ac 13:5, 13, this disciple is simply called John. However, here and at Ac 12:25; 15:37, his Roman surname, Mark, is also given. Elsewhere in the Christian Greek Scriptures, he is referred to simply as Mark.​—Col 4:10; 2Ti 4:11; Phm 24; 1Pe 5:13.

It is his angel: Both the Hebrew and the Greek terms rendered “angel” mean “messenger.” (See study note on Joh 1:51.) Those who referred to “his [Peter’s] angel” may have assumed that an angelic messenger representing the apostle was at the gate. It appears that some Jews believed that each servant of God had his own angel​—in effect, a guardian angel, a view that is not directly taught in God’s Word. Jesus’ disciples knew, though, that throughout history, angels rendered personal assistance to God’s people. For example, Jacob spoke of “the angel who has been recovering me from all calamity.” (Ge 48:16) Also, Jesus said of his disciples that “their angels in heaven always look upon the face of my Father,” showing that angels take an active interest in each of Jesus’ disciples. (See study note on Mt 18:10.) Those gathered at Mary’s house would not have imagined that Peter himself was appearing in some angelic form, as if he had died and was now a spirit; they knew what the Hebrew Scriptures said about the condition of the dead.​—Ec 9:5, 10.

Jehovah: Most Greek manuscripts use the term “the Lord” (Greek, ho Kyʹri·os) here. However, as explained in App. C, there are a number of reasons to believe that the divine name was originally used in this verse and later replaced by the title Lord. Therefore, the name Jehovah is used in the main text.​—See App. C3 introduction; Ac 12:17.

James: Most likely referring to Jesus’ half brother. He may have been next to Jesus in age, being the first named of Mary’s four natural-born sons: James, Joseph, Simon, and Judas. (Mt 13:55; Mr 6:3; Joh 7:5) James was an eyewitness at Pentecost 33 C.E. when thousands of visiting Jews from the Diaspora responded to the good news and got baptized. (Ac 1:14; 2:1, 41) Peter instructed the disciples to “report . . . to James,” indicating that James was taking the lead in the Jerusalem congregation. He is apparently also the James mentioned at Ac 15:13; 21:18; 1Co 15:7; Ga 1:19 (where he is called “the brother of the Lord”); 2:9, 12 and the one who wrote the Bible book bearing his name.​—Jas 1:1; Jude 1.

the man in charge of the king’s household affairs: Lit., “the man over the king’s bedchamber.” Apparently, this was a highly respected person who was entrusted with considerable responsibility for the king’s house and personal affairs.

angel of Jehovah: See study note on Ac 5:19 and App. C3 introduction; Ac 12:23.

the word of Jehovah: See study note on Ac 8:25 and App. C3 introduction; Ac 12:24.

the relief work: Or “the relief ministry.”​—See study note on Ac 11:29.