3:7–9 Crowds are flocking to John to be baptized, but he does not celebrate their arrival in the wilderness. He identifies them as the offspring of the Serpent (cf. Matt. 3:7; 12:34; 23:33; cf. also Gen. 3:15; John 8:44). John warns them about the wrath that will be poured out on the last day (cf. Rev. 6:16–17), on the day of the Lord—a common theme in the OT (Isa. 13:9; Amos 5:18–20; Zeph. 1:14–15; 2:2; Mal. 4:1). John’s words refute the notion that his baptism itself, as a mechanical act, will protect them from the impending judgment. They must produce fruit that accords with repentance, fruit that verifies their repentance as a reality.

Paul makes the equivalent statement in Acts 26:20: “They should repent and turn to God, performing deeds in keeping with their repentance.” Claiming a genealogical relationship with Abraham is insufficient. Someone can claim Abraham as one’s father when one does not belong to him (Luke 16:24; John 8:33–40). One must share the faith of Abraham, as Paul teaches, to be a child of Abraham (Rom. 4:9–12; Gal. 3:6–9). Physical descent from Abraham is not sufficient because the Lord could, if he wished, turn stones into Abraham’s children, and hence people should not rejoice merely over being descendants of the Patriarch.

The day of judgment is at hand, since even now the axe is poised to strike at trees bereft of fruit. Trees that do not produce fruit will be cut down and cast into the fire; this image clearly denotes the final judgment awaiting those who are not truly repentant (cf. Isa. 66:15–16, 24; Zeph. 1:18; 3:8; Luke 9:54; 17:29; John 15:6).

3:10–14 John now offers examples of what true repentance looks like. The crowds in Luke 3:10 show that they have not ignored John’s words of warning in verses 7–9, nor do they reject his admonition. Instead they respond with humility and teachability, inquiring what they should do to demonstrate that they are truly repentant. We see the same response to Peter’s Pentecost sermon in Acts 2:37. John addresses the crowd generally, showing that the first evidence of repentance is generosity and concern for those in need. Thus those who have more than they need are to share with those who have nothing. The person who has an extra tunic should share with those who have none. The “tunic” refers to clothing worn next to the skin (Matt. 5:40; Luke 6:29). In the same way, those who have food should share with those who are going hungry. James makes the same point when he says that true faith manifests itself in works—in clothing the cold and feeding the poor (James 2:15–17; cf. Job 31:16–20; Isa. 58:7; Ezek. 18:7).

Tax collectors, who are often addressed in the Gospel (Luke 5:27, 29; 7:29, 34; 15:1; 18:10, 13; 19:2) and come to John to submit to baptism, also query John about what they should do, identifying him as a teacher. The tax system in the Roman world was complicated: “There were different ranks of collectors, and there were different taxes to collect. The system of collection was known as tax (or toll) farming. City rulers leased the right to collect taxes to an individual or group, who had bid for this right and had paid for it in advance.”39 Various taxes were assessed, making the system complex and liable to misuse. Tax collectors were assigned to collect the necessary taxes and added an extra fee for their own profit. John does not ask tax collectors to resign and join him in the wilderness. Instead they are to do their job honestly, refusing bribes and desisting from skimming money off the top for themselves.

Soldiers also approach John, asking how they should respond. Most think these soldiers are Jewish.40 We should begin by noting what John does not say to the soldiers. We might expect him to say that they should cease serving as soldiers and take up another vocation. But John does not expect people to imitate his lifestyle, living in the wilderness apart from society. Nor does he reject a military calling. Instead soldiers are to avoid using force to shake people down and depriving people of money by fraudulent means. Soldiers must not use their power to oppress others but ought to be content with the wages they receive.