Luke 3:1–6 - Now in the fifteenth year of the reign of Tiberius Caesar, when Pontius Pilate was governor of Judea, and Herod was tetrarch of Galilee, and his brother Philip was tetrarch of the region of Ituraea and Trachonitis, and Lysanias was tetrarch of Abilene, 2 in the high priesthood of Annas and Caiaphas, the word of God came to John, the son of Zacharias, in the wilderness. 3 And he came into all the district around the Jordan, preaching a baptism of repentance for the forgiveness of sins; 4 as it is written in the book of the words of Isaiah the prophet . . .
The Gospel’s Historicity (vv 1-2) - Luke gives a historian’s “exact dating with an elaborate chronological synchronism reminiscent of Thucydides 2:2” (Marshall, NIGTC). “Luke is well informed” “and familiar with official language” of a Roman governor (Bovon, Hermeneia). He is exceptionally knowledgable of the setting, e.g., “Under the high priest Annas-Caiaphas” “they discharged the duties” of high priest (singular) (Plummer, ICC). Luke-Acts provides inscriptions, titles, events, function of town assemblies, land markers, historical details, names, as well language with informed medical, scientific, philosophical, and geographic detail (cf Sir William Ramsay: The Bearing of Recent Discoveries on the Trustworthiness of the New Testament, 1953). Just as Luke promised (1:4), this Gospel gives “certainty” (asphaleia, security) as a witness to Jesus. Despite Luke’s specificity, dating in the ancient world depended on “when” a person began to reign, which is subject to variations. “We do not know whether this includes his becoming co-emperor with Augustus in AD 11 or 12, which would add up to AD 26 or 27, or whether this refers to his sole rule after Augustus’s death in AD 14, which would yield the date AD 29” (Balch, Eerdmans). This point highlights that Christianity virtually created exactness in recording history by which we may assert it: is Dec. 9, 2018, anno Domini.
The Gospel’s Sacramentality (vv 3-4) - John (a 30 year old priest) was “in the spirit and power of Elijah” who divided the water of the Jordan (2Kgs. 2:8ff). He prepared Israel for Jesus to be “manifest” (Jn. 1:31) by “preaching a baptism of repentance for the forgiveness of sins” at the Jordan river (Lk. 1:3). Like previous baptisms of Israel, John led a remnant Israel “beyond the Jordan” in “a symbolic exodus from Jerusalem and Judea” “in order to reclaim the land in a quasi-reenactment of the return from the Babylonian exile” (Colin Brown). Unfortunately, the leaders of Israel “rejected God’s purpose for themselves, not having been baptized by John” (Lk. 7:30). God always confirms His covenant promises with a covenant sign, a sacrament. In this transitional time, the sign was John’s baptism. Then the preparation would “decrease” in light of the present redemptive kingdom of Jesus bringing forgiveness and restoration. This rule/kingdom was prophesied by Isaiah and fulfilled all the OT promises. “All flesh will see the salvation [glory] of God” (Lk. 1:6; Is. 40:5).