3:1-2 Luke made detailed reference to the time when John commenced his ministry to document the reliability of his Gospel.116Only the reference to Tiberius is necessary to date the beginning of John's ministry that shortly preceded the commencement of Jesus' ministry. The other references place these events in a broader historical context.
Pontius Pilate was governor (prefect) of Judea from 26 to late 36 or early 37 A.D. Herod Antipas ended his reign as tetrarch of Galilee that began in 4 B.C. by deposition in 39 A.D. His brother Herod Philip, who ruled territories to the northeast of Palestine from 4 B.C., died in 34 A.D. Archaeological evidence does not enable scholars to date Lysanias, the tetrarch of Abilene, an area northeast of Damascus. Annas was Israel's high priest from 6 to 15 A.D. until the Roman authorities deposed him. However the Jews continued to regard him as the high priest, and he retained his title.117His son-in-law Caiaphas served as the official high priest from 18 to the spring of 37 A.D. Thus the general time frame when John began his ministry was between 26 and the spring of 37 A.D. The specific date, the fifteenth year of Tiberius Caesar, is harder to pinpoint, but it was probably 29 A.D.118
Then the word of God came to John in the wilderness where he lived (cf. 1:80). He began his ministry as a prophet then (cf. Isa. 1:1; Jer. 1:1-3; et al.).
3:3 Luke mentioned John's itinerant ministry in the region around the Jordan River whereas Matthew described it as in the wilderness of Judea (Matt. 3:1). The thing that characterized John's ministry in the minds of his contemporaries was his baptism. What marked his baptism distinctively was that it expressed repentance that resulted in divine forgiveness of sins. John's baptism prefigured Jesus' different kind of baptism (cf. v. 16). Luke said little about John's baptizing but stressed his preaching.
"The task of proclaiming . . . repentance for release of sins' (3:3) remains central throughout Luke-Acts [cf. 4:18; 5:17-32; 24:47]."119
3:4-6 All three synoptic writers quoted Isaiah 40:3 as the prophecy that John fulfilled, and John the evangelist recorded John the Baptist quoting it of himself (cf. John 1:23). However, Luke alone also quoted Isaiah 40:4-5. These verses contained the preparations made for a royal visitor that were common in the Greco-Roman world. They also included the fact that all people would experience the salvation that God would provide. One of Luke's main themes was the universal scope of salvation (cf. 2:30; Acts 28:28; et al.).120Typically Luke quoted from the Septuagint. John's ministry consisted of preparing the Jews by getting them right with God so when Messiah appeared they would believe on Him.
"This quotation from Isaiah not only interprets John's special mission but reveals the purpose of God which underlies the whole narrative of Luke-Acts."121
In Luke, John is a "prototype of the Christian evangelist."122
"The section on John's ministry begins with a rather lengthy scriptural quotation and ends with an arrest that will lead to death. Jesus' ministry will begin and end in the same way."123
