Read Isaiah 40 in its entirety, a beautiful passage of consolation to sinful Israel. Also read Matthew 3:1-3; Mark 1:1-3, and John 1:23.
With the death of Herod the Great, the prophecy in Genesis 49:10 was fulfilled. With Herod the scepter departed from Judah. Palestine was split up among his sons.
Ylvisaker: The nation which had been in such flourishing condition in the days of David and Solomon, which had ruled over the nations, and whose name was known far and wide, had now become abjectly passive and non-resistant.
Five political rulers, in a descending scale, are enumerated. The dating of John's appearance follows the pattern for dating used by ancient historians.
When was the fifteenth year of the rule of Tiberius? Scholars are divided. Was it 28/29, excluding several years of co-regency between Augustus and Tiberius or was it 25/26, including these years of co-regency? The date 25/26 harmonizes with Luke 3:23 where Jesus' age, at the beginning of his public ministry, is "about thirty years."
Herod is Herod Antipas. Luke mentions him often: 3:19; 8:3; 9:7,9; 13:31; Acts 4:27; 13:1. He was prince of Galilee during the entire life of Jesus and was the one who caused the death of John the Baptist.
Here we have ecclesiastical dating. The word for high priest is singular. Caiaphus was the actual high priest while Annas, his father-in-law, now deposed, was very influential. Note that Annas is mentioned first.
"The word of God came," denotes both the call and the content of John's message. He was called just as were the other prophets. Look at Jeremiah 1:2 and 2:1.
There had been no prophecy for four hundred years. Read Luke 1:14-17 and 1:76-79.
Beck: Then God spoke to John, the Son of Zacharias, in the wilderness.
Plainly the Lord told John where to preach. John preached on both sides of the Jordan River, from the Sea of Galilee to the Dead Sea. This verse does not say that John did not baptize. It gives a summary of his preaching.
Beck: He preached: 'Repent and be baptized to have your sins forgiven.
"Repent" is used in a wide sense denoting contrition and faith. It was a contrition-and-faith baptism. Luke uses this word frequently. Look at 3:8; 5:32; 15:7; 24:47.
Remember Luther's words: "Where there is forgiveness of sins, there is life and salvation." Look again at Luke 1:77.
John preached law to show people their sins but he also preached clear Gospel. Lutherans stand alone in their understanding of baptism as a true means of grace. For three reasons we must stand firm in this understanding.
In Luke 7:30 Jesus calls John's baptism the gracious plan of God. It was essentially the same as later baptism.
Ephesians 4:4 speaks of "one Lord, one faith, one baptism." That is repeated by the Nicene Creed: " I acknowledge one baptism for the forgiveness of sins."
John 1:31 clearly tells us that the water-baptism of John revealed Christ to Israel and through that baptism Jesus was baptizing Israel with the Holy Spirit.
John 4:1-3 tells us that John and Jesus's disciples baptized side by side. John's baptism, a true means of grace, looked forward to the complete fulfillment and was for all nations. Perhaps instead of calling them Johannine and Christian baptism, we ought refer to them as the Old Covenant and New Covenant baptism, lest we give the impression that John's baptism was not Christian.
"As it is written" means it stands on record with lasting results. Ever since it was written by inspiration.
Matthew, Mark and Luke quote the first three lines alike. These words are from the LXX. They change the word LORD to mean Christ. The divinity of Christ is implicit.
"In the desert" is figurative in Isaiah, denoting the miserable condition of Israel. Here in Luke the words are literal.
A great King, Jesus, is coming. Make the road on which He is coming straight. This, of course, denotes confession of sins, repentance, and Christian living which follows repentance.
Arndt: The obstacles that are in the way -- self-righteousness, spiritual pride, the submission to the dictates of haughty reason, the love of sin in its various forms, unbelief, and despair -- are to be removed. . . . Valleys may be said to symbolize weakness of faith, discouragement, lack of trust in God's promises. The opposite extreme would be pointed to by hills and mountains -- haughtiness of spirit, pride of intellect and heart, presumptuous judging of God's will and criticizing His ways. The crookedness and the roughness pointed to are apt designations of sinful conduct, taking a person away from the straight, smooth path of God's commandments.
In other words, the second use of the Law: "By the law is the knowledge of sin."
A beautiful statement of the universal atonement and the universal nature of the preaching of the Gospel. Compare John 1:29: "Look, the Lamb of God, who takes away the sin of the world!"
John preached primarily to Israel but already announced the universality of Christ's atonement. No Jew could claim that he misunderstood.