Although most Jewish traditions acknowledged that all people need some repentance (see 1 Kings 8:46; 1 Esdras 4:37-38; Sirach 8:5), John's call to his people (Mt 3:5-6, 8-9) is more radical. John's "repentance" refers not to a regular turning from sin after a specific act but to a once-for-all repentance, the kind of turning from an old way of life to a new that Judaism associated with Gentiles' converting to Judaism. True repentance is costly: the kingdom "demands a response, a radical decision. . . . Nominalism is the curse of modern western Christianity" (Ladd 1978a:100). In various ways John warns his hearers against depending on the special privileges of their heritage.

First, John's baptism confirms that he is calling for a once-for-all turning from the old way of life to the new, as when Gentiles convert to Judaism. Although Judaism practiced various kinds of regular ceremonial washings, only the baptism of Gentiles into Judaism paralleled the kind of radical, once-for-all change John was demanding. In other words, John was treating Jewish people as if they were Gentiles, calling them to turn to God on the same terms they believed God demanded of Gentiles. As F. F. Bruce puts it, "If John's baptism was an extension of proselyte baptism to the chosen people, then his baptism, like his preaching, meant that even the descendants of Abraham must . . . enter . . . by repentance and baptism just as Gentiles had to do" (1978:61).

Second, John's hearers were not all good descendants of their ancestors anyway. "Viper" was certainly an insult, and brood of vipers (offspring of vipers) carries the insult further. In the ancient Mediterranean many people thought of vipers as mother killers. In the fifth century B.C. Herodotus declared that newborn Arabian vipers chewed their way out of their mothers' wombs, killing their mothers in the process. Herodotus believed that they did so to avenge their fathers, who were slain by the mothers during procreation (Herod. Hist. 3.109). Later writers applied his words to serpents everywhere (Aelian On Animals 1.24; Pliny N.H. 10.170; Plut. Divine Vengeance 32, Mor. 567F). Calling John's hearers vipers would have been an insult, but calling them a brood of vipers accused them of killing their own mothers, indicating the utmost moral depravity. That Matthew applies this phrase to religious leaders may be unfortunately significant.

Third, employing the image of a tree's fruit, both John and Jesus demand that one's life match one's profession (3:8; 7:16-17; 12:33; 13:22-23; 21:34, 43). In contrast to some forms of modern Christianity, Judaism also insisted that repentance be demonstrated practically (m. Yoma 8:8-9; Montefiore 1968:2:15). Thus no one could simply appeal to ethnic character or descent from Abraham (compare Deut 26:5). Biblical tradition had already applied the image of a tree being cut down (Ezek 31:12-18; Dan 4:23) or burned (Jer 11:16) to the judgment of a nation. Most small trees that could not bear fruit would have been useful, especially for firewood (N. Lewis 1983:139).

Fourth, John's admonition that out of stones God could raise up children for Abraham (compare Gen 1:24; 2:9) warns his hearers not to take their status as God's people for granted. Jewish people had long believed they were chosen in Abraham (Neh 9:7; Mic 7:20; E. Sanders 1977:87-101), but John responds that this ethnic chosenness is insufficient to guarantee salvation unless it is accompanied by righteousness (compare Amos 3:2; 9:7). Prophets were not above using witty wordplay at times (Amos 8:1-2; Mic 1:10-15; Jer 1:11-12), and children and stones probably represent a wordplay in Aramaic; the two words sound very similar (Manson 1979:40). (At any rate, John's symbolism should not have been obscure: God had previously used stones to symbolize his people in Ex 24:4; 28:9-12; Josh 4:20-21.)

Salvation demands personal commitment, not merely being part of a religious or ethnic group. No one can take one's spiritual status for granted simply because one is Jewish, Catholic, Baptist, evangelical or anything else. As the saying goes, God has no grandchildren; the piety of our upbringing cannot save us if we are not personally committed to Christ. Even depending on our past religious experience is precarious. Whereas historic Calvinism teaches that the elect will persevere to the end and Arminianism allows that apostate converts may be lost, neither supports the now-common view that those who pray the sinner's prayer but return to a life of ignoring God will be saved. Yet at a popular level, vast numbers of people believe they are saved because they once prayed a prayer. If this modern popular misunderstanding of the once-saved-always-saved doctrine is false, it may be responsible for millions of people's assuming they are saved when they are in fact lost. John's message constituted a decisive challenge to false doctrines of his day that cost people their salvation; John's successors in our day must be prepared to issue the same sort of unpopular challenges.