Mark 1:4-5
4 John did baptize in the wilderness, and preach the baptism of repentance for the remission of sins.
5 And there went out unto him all the land of Judaea, and they of Jerusalem, and were all baptized of him in the river of Jordan, confessing their sins.
Abridged Commentary - Mark 1:4-5
1:4-5 The baptism of John the Baptist was one of national repentance for the Jewish people, preparing the way for the Messianic Kingdom (Matthew 3:2, 4:17, Mark 1:14-15). The remission of sins spoken of in this context (Luke 3:3) is temporal, and signifies that one is embracing the Kingdom, and in fellowship with God. The barren trees which are cut down, and thrown into the fire (Matthew 3:10-12, Luke 3:9, 3:16-17) are individuals who are not embracing the Messianic Age, and this comes to be embodied in the nation of Israel as a whole (Matthew 8:11-12, 21:33-43). The "fire" is temporal judgment, and one such instance of this judgment can be seen in the destruction of the Jewish nation in 70-135 AD.
The Grace New Testament Commentary - Mark 1:4-5
1:4 John is identified as the messenger who appears in the wilderness. The wilderness is where Israel expected the messenger to appear. Although the temple was in Jerusalem, Ezekiel had documented the glory of God leaving the city (Ezek 11:23). Jerusalem was hostile toward Jesus throughout the Gospels (cf. Matt 23:37) and because of its corruptness, God is calling the people into the wilderness to identify with His prophet.
Baptism became such a trademark of John's ministry that he became known as John the Baptizer. His ministry involved a baptism of repentance for the remission of sins. Many equate this with the message of eternal life. In this view repentance is a synonym for faith resulting in justification, with baptism as the first step of discipleship.
However, this view is flawed. First, repentance and faith are not synonyms (cf. Mark 1:15; Acts 20:21). Second, such attempts ignore the historical offer of the kingdom to Israel. Third, the Apostle Paul's interpretation of John's baptism identifies it as temporary and preparatory (cf. Acts 19:1-7).
A better view is to understand that John was calling Israel to repent in order to restore fellowship with God and receive the kingdom. While repentance does not grant eternal life, it prepares their hearts to receive the Messiah (cf. Acts 19:4). The evidence of repentance was expressed by water baptism. The genitive metanoias could function as a genitive of source, that is, "a baptism arising out of repentance," or of description, "a baptism characterized by repentance."
1:5 The appearance of John resulted in a response from all of Judea and those from Jerusalem. Those John baptized were confessing their sins.
Charles Bing - Grace, Salvation, and Discipleship - John's Baptism of Repentance, Matthew 3:1-12 (cf. Mark 1:2-8, Luke 3:3-17)
(Salvation) Interpretation: John the Baptist baptized unbelievers who repented of sins and changed their conduct so that they would be saved.
(Discipleship) Interpretation: John the Baptist baptized Jews who wanted to show their repentance under the Mosaic Covenant, separate from sinful Israel, and prepare for the coming Messiah.
This is a passage where it is important to understand the setting and context. John the Baptist has a message for the nation of Israel about repentance and baptism. But is he telling them as well as people today how to be saved?
At the time that John preached, the nation of Israel was still under the Mosaic Covenant. For God's covenant people, the way to be restored from departing from God was to repent - to change their minds or attitudes about their sin (Deut. 30:2, 10: 2 Chr. 7:14). At that point, they are prepared to receive the Messiah that John would introduce. His baptism was a witness to their repentance and anticipation of the Messiah. The works he tells the Pharisees, Sadducees, and others to do (Matt. 3:7-9; Luke 3:7-14) are works that are consistent with true repentance, not works that will save them. This passage clearly differentiates between repentance as an inner attitude and "fruits worthy of repentance" which is the outer conduct (v. 8).
It helps to see what the apostle Paul says about John's baptism in Acts 19:4. Speaking to Ephesians who had received John's baptism but had not believed in Jesus Christ, he said, "John indeed baptized with a baptism of repentance, saying to the people that they should believe on Him who would come after him, that is, on Jesus Christ." Those who had received John's baptism were Jewish believers who needed to become Christians through faith in Jesus Christ. They were in the transition period between the era of Law and the era of grace.
As recorded in Acts 13:24, Paul said in Pisidian Antioch before Christ officially presented Himself to Israel as the Messiah, that John preached "the baptism of repentance to all the people of Israel." If we understand the Jewish audience and the covenantal background for John's preaching of baptism and repentance, we should not make this a template for preaching the gospel in the church age. First, this does not at all speak of Christian baptism. Second, repentance does not save anyone in and of itself, but the change of heart that it reflects is well prepared to believe in the Savior. Though it addresses God's people under His covenant, we can learn from this as a general (Discipleship message) that teaches the way back to God begins with a change of mind and heart.
Thomas Constable's Expository Notes on the Bible - Mark 1:4
1:4 John baptized people when they gave evidence of "repentance" (Gr. metanoia). "A baptism of repentance" means a baptism characterized by repentance. The Jews whom John baptized not only changed their minds, the basic meaning of metanoia, but they also changed their behavior. This is the only occurrence of metanoia in Mark. The change in their thinking - regarding their sinfulness and the necessity to get right with God in view of the messianic kingdom being at hand - resulted in the forgiveness of their sins (cf. Matt. 12:41; Acts 2:38). Change of behavior does not earn forgiveness, but change of behavior demonstrates a genuine change of mind - from believing that one is righteous to believing that one is sinful and in need of salvation - that results in forgiveness. Neither does baptism result in forgiveness of sins, as some advocate. Rather, baptism demonstrated true repentance, which led to the forgiveness of sins.