John Dominic Crossan
Crossan makes almost no use of this saying in [Historical Jesus], simply noting (353) that unlike some sayings concerned with opposition and hostility to the messengers of the open secret, this saying could go back to Jesus himself.
The Seminar opted for "Sly as a Snake" as the title for this cluster, despite using the Sayings Parallels (with its "Serpents and Doves") as the basic workbook for the sayings of Jesus. While the saying was considered something that Jesus may have said, the commentary in [The Five Gospels] (170 & 495) suggests that the saying may have been a proverb quoted by Jesus rather than something created by him.
Samuel T. Lachs
Lachs [Rabbinic Commentary on the New Testament] (181) suggests that the Greek phronimoi is better translated as "shrewd, crafty or cunning" reflecting its use in the LXX at Gen 3:1. He notes that the serpent and the dove are described in rabbinic literature with precisely the same adjectives as here [see Mid. Ps. 28.2 (115a), 119.1 (244b); Lev. R. 33] and cites the following rabbinic tradition concerning Song 2:14 ("my dove is in the cleft of the rock"):
R. Judah said in the name of R. Simeon: 'With me they are innocent as doves, but with the nations of the world they are like cunning serpents.' [Cant. R. 2.14]
Lüdemann [Jesus] (167) dismisses Matt 10:16b as "redactional" and does not even discuss it when analyzing the section in Matt 10:16-26a. When discussing the GThom version, Lüdemann suggests that the text "derives from Matt. 10.16b, for that passage is redactional" (609). He concludes that the whole of Thom 39 is derived from Matthew, since the earlier verses are equivalent to Matt 23:13 and in both Thomas and Matthew the saying is directed against Pharisees and scribes.
John P. Meier
Meier does not discuss this saying in the first three volumes of Marginal Jew.