A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
luk 3:1PREACHING, BAPTISM, AND IMPRISONMENT OF JOHN. (Luke 3:1-20)
Here the curtain of the New Testament is, as it were, drawn up, and the greatest of all epochs of the Church commences. Even our Lord's own age (Luk 3:23) is determined by it [BENGEL]. No such elaborate chronological precision is to be found elsewhere in the New Testament, and it comes fitly from him who claims it as the peculiar recommendation of his Gospel, that he had "accurately traced down all things from the first" (Luk 1:3). Here, evidently, commences his proper narrative. Also see on Mat 3:1.
the fifteenth year of Tiberius--reckoning from the period when he was admitted, three years before Augustus' death, to a share of the empire [WEBSTER and WILKINSON], about the end of the year of Rome 779, or about four years before the usual reckoning.
Pilate . . . governor of Judea--His proper title was Procurator, but with more than the usual powers of that office. After holding it about ten years he was ordered to Rome, to answer to charges brought against him, but ere he arrived Tiberius died (A.D. 35), and soon after Pilate committed suicide.
Herod--(See on Mar 6:14).
Philip--a different and very superior Philip to the one whose wife Herodias went to live with Herod Antipas. (See Mar 6:17).
Iturea--to the northeast of Palestine; so called from Ishmael's son Itur or Jetur (Ch1 1:31), and anciently belonging to the half tribe of Manasseh.
Trachonitis--farther to the northeast, between Iturea and Damascus; a rocky district, infested by robbers, and committed by Augustus to Herod the Great to keep in order.
Abilene--still more to the northeast, so called from Abila, eighteen miles from Damascus [ROBINSON].
luk 3:2Annas and Caiaphas . . . high priests--the former, though deposed, retained much of his influence, and, probably, as sagan or deputy, exercised much of the power of the high priesthood along with Caiaphas (Joh 18:13; Act 4:6). Both Zadok and Abiathar acted as high priests in David's time (Sa2 15:35), and it seems to have become the fixed practice to have two (Kg2 25:18). (Also see on Mat 3:1.)
word of God came unto John--Such formulas, of course, are never used when speaking of Jesus, because the divine nature manifested itself in Him not at certain isolated moments of His life. He was the one everlasting manifestation of the Godhead--THE WORD [OLSHAUSEN].
luk 3:5Every valley, &c.--levelling and smoothing, obvious figures, the sense of which is in the first words of the proclamation, "Prepare ye the way of the Lord."
luk 3:6all flesh, &c.--(quoted literally from the Septuagint of Isa 40:5). The idea is that every obstruction shall be so removed as to reveal to the whole world the Salvation of God in Him whose name is the "Saviour" (compare Psa 98:3; Isa 11:10; Isa 49:6; Isa 52:10; Luk 2:31-32; Act 13:47).
luk 3:10What shall we do then?--to show the sincerity of our repentance. (Also see on Mat 3:10.)
luk 3:11two coats--directed against the reigning avarice. (Also see on Mat 3:10.)
luk 3:12publicans, &c. (Also see on Mat 3:10.)
luk 3:13Exact no more, &c.--directed against that extortion which made the publicans a byword. (See on Luk 19:2; Luk 19:8). (Also see on Mat 3:10.)
luk 3:14soldiers . . . Do violence to none--The word signifies to "shake thoroughly," and so to "intimidate," probably in order to extort money or other property. (Also see on Mat 3:10.)
accuse . . . falsely--acting as informers vexatiously, on frivolous or false grounds.
content with your wages--"rations." We may take this as a warning against mutiny, which the officers attempted to suppress by largesses and donations [WEBSTER and WILKINSON]. And thus the "fruits" which would evidence their repentance were just resistance to the reigning sins, particularly of the class to which the penitent belonged, and the manifestation of an opposite spirit.
luk 3:15whether he were the Christ--showing both how successful he had been in awakening the expectation of Messiah's immediate appearing, and the high estimation, and even reverence, which his own character commanded. (Also see on Mat 3:10.)
luk 3:16John answered--either to the deputation from Jerusalem (see Joh 1:19, &c.), or on some other occasion, simply to remove impressions derogatory to his blessed Master which he knew to be taking hold of the popular mind. (Also see on Mat 3:10.)
saying unto them all--in solemn protestation. So far from entertaining such a thought as laying claim to the honors of Messiahship, the meanest services I can render to that "Mightier than I that is coming after me," are too high an honor for me. Beautiful spirit, distinguishing this servant of Christ throughout!
one mightier than I--"the Mighter than I."
luk 3:18many other things, &c.--such as we read in Joh 1:29, Joh 1:33-34; Joh 3:27-36. (Also see on Mat 3:12.)
luk 3:19But Herod, &c.--See on Mar 6:14, &c. (Also see on Mat 3:12.)
and for all the evils which Herod had done--important fact here only mentioned, showing how thoroughgoing was the fidelity of the Baptist to his royal hearer, and how strong must have been the workings of conscience in that slave of passion when, notwithstanding such plainness, he "did many things and heard John gladly" (Mar 6:20, Mar 6:26).
luk 3:20Added yet, &c.--(Also see on Mat 3:12).
luk 3:21BAPTISM OF AND DESCENT OF THE SPIRIT UPON JESUS. (Luk 3:21-22)
when all the people were baptized--that He might not seem to be merely one of the crowd. Thus, as He rode into Jerusalem upon an ass, "whereon yet never man sat" (Luk 19:30), and lay in a sepulchre "wherein was never man yet laid" (Joh 19:41), so in His baptism He would be "separate from sinners."
luk 3:23GENEALOGY OF JESUS. (Luke 3:23-38)
he began to be about thirty--that is, "was about entering on His thirtieth year." So our translators have taken the word (and so CALVIN, BEZA, BLOOMFIELD, WEBSTER and WILKINSON, &c.): but "was about thirty years of age when He began [His ministry]," makes better Greek, and is probably the true sense [BENGEL, OLSHAUSEN, DE WETTE, MEYER, ALFORD, &c.]. At this age the priests entered on their office (Num 4:3).
being, as was supposed, the son of Joseph, &c.--Have we in this genealogy, as well as in Matthew's, the line of Joseph? or is this the line of Mary?--a point on which there has been great difference of opinion and much acute discussion. Those who take the former opinion contend that it is the natural sense of this verse, and that no other would have been thought of but for its supposed improbability and the uncertainty which it seems to throw over our Lord's real descent. But it is liable to another difficulty; namely, that in this case Matthew makes Jacob, while Luke makes "Heli," to be Joseph's father; and though the same man had often more than one name, we ought not to resort to that supposition, in such a case as this, without necessity. And then, though the descent of Mary from David would be liable to no real doubt, even though we had no table of her line preserved to us (see, for example, Luke 1:2-32, and see on Luk 2:5), still it does seem unlikely--we say not incredible--that two genealogies of our Lord should be preserved to us, neither of which gives his real descent. Those who take the latter opinion, that we have here the line of Mary, as in Matthew that of Joseph--here His real, there His reputed line--explain the statement about Joseph, that he was "the son of Hell," to mean that he was his son-in-law, as the husband of his daughter Mary (as in Rut 1:11-12), and believe that Joseph's name is only introduced instead of Mary's, in conformity with the Jewish custom in such tables. Perhaps this view is attended with fewest difficulties, as it certainly is the best supported. However we decide, it is a satisfaction to know that not a doubt was thrown out by the bitterest of the early enemies of Christianity as to our Lord's real descent from David. On comparing the two genealogies, it will be found that Matthew, writing more immediately for Jews, deemed it enough to show that the Saviour was sprung from Abraham and David; whereas Luke, writing more immediately for Gentiles, traces the descent back to Adam, the parent stock of the whole human family, thus showing Him to be the promised "Seed of the woman." "The possibility of constructing such a table, comprising a period of thousands of years, in an uninterrupted line from father to son, of a family that dwelt for a long time in the utmost retirement, would be inexplicable, had not the members of this line been endowed with a thread by which they could extricate themselves from the many families into which every tribe and branch was again subdivided, and thus hold fast and know the member that was destined to continue the lineage. This thread was the hope that Messiah would be born of the race of Abraham and David. The ardent desire to behold Him and be partakers of His mercy and glory suffered not the attention to be exhausted through a period embracing thousands of years. Thus the member destined to continue the lineage, whenever doubtful, became easily distinguishable, awakening the hope of a final fulfilment, and keeping it alive until it was consummated" [OLSHAUSEN].
luk 3:24son of Matthat, &c.--(See on Mat 1:13-15). In Luk 3:27, Salathiel is called the son, while in Mat 1:12, he is called the father of Zerubbabel. But they are probably different persons.
luk 3:38son of God--Compare Act 17:28.