Josephus, Antiquities, 18.116-119
Written c. 94 CE. Some have disputed the authenticity of this passage, but it is extant as early as 248CE, as it is referred to in Origen’s Contra Celsus 1.47.

The relevant text reads (my highlighting)

Source: LCL 433:81-85

• But to some of the Jews the destruction of Herod’s army seemed to be divine vengeance, and certainly a just vengeance, for his treatment of John, surnamed the Baptist. For Herod had put him to death, though he was a good man and had exhorted the Jews to lead righteous lives, to practise justice towards their fellows and piety towards God, and so doing to join in baptism. In his view this was a necessary preliminary if baptism was to be acceptable to God. They must not employ it to gain pardon for whatever sins they committed, but as a consecration of the body implying that the soul was already thoroughly cleansed by right behaviour. When others too joined the crowds about him, because they were aroused to the highest degree by his sermons, Herod became alarmed. Eloquence that had so great an effect on mankind might lead to some form of sedition, for it looked as if they would be guided by John in everything that they did. Herod decided therefore that it would be much better to strike first and be rid of him before his work led to an uprising, than to wait for an upheaval, get involved in a difficult situation and see his mistake. Though John, because of Herod’s suspicions, was brought in chains to Machaerus, the stronghold that we have previously mentioned, and there put to death, yet the verdict of the Jews was that the destruction visited upon Herod’s army was a vindication of John, since God saw fit to inflict such a blow on Herod. (Josephus, Antiquities, 18.116-119)

It’s unclear whether to make a case of an interpolation by a Christian scribe here, because why would the reason for John’s death be so different here from the gospels? Anyway, a key difference is we have a divine reaction by God here in Josephus, as opposed to the death of John the Baptist in Mark, but like with Jesus’ death. What I would like to point to here is baptism is not meant to get rid of sin, but Josephus says:

• to lead righteous lives, to practise justice towards their fellows and piety towards God, and so doing to join in baptism. In his view this was a necessary preliminary if baptism was to be acceptable to God. They must not employ it to gain pardon for whatever sins they committed, but as a consecration of the body implying that the soul was already thoroughly cleansed by right behaviour.

And so we have an exact parallel in Josephus with the ultimate point of the New Testament of moving beyond the crude and commonplace “appeasing God’s wrath at sin” Penal Substitution theology to a deeper understanding of Jesus as the Yom Kippur goats/Passover Lamb with Moral Influence theology. This seems more to suggest that Mark was familiar with Josephus rather than a Christian scribe interpolated into Josephus, pushing the date of Mark forward post 95 CE, which I have posted on before; however, this Moral Influence theology is also in Paul, so it’s unclear what the ultimate source is. For further analysis,

See: Corporate Sin Post Script: Did The Historical Jesus Know John The Baptist? (My Last Blog Post For A Little While)