“From My Flesh I Will See God”
From rabbinic texts—albeit quite a bit later than Paul—we actually learn of the view hypothesized as a genuine Jewish theologoumenon. Some of the Rabbis read circumcision as a necessary preparation for seeing God, the summum bonum of late-antique religious life (Boyarin 1990a). This is, of course, an entirely different hermeneutic structure from platonic allegorizing, because although a spiritual meaning is assigned to the corporeal act, the corporeal act is not the signifier of that meaning but its very constitution. That is, circumcision here is not the sign of something happening in the spirit of the Jew, but it is the very event itself—and it is, of course, in his body. Moreover, as I have argued elsewhere, for the rabbinic formation, this seeing of God was not understood as the spiritual vision of a platonic eye of the mind, but as the physical seeing of fleshly eyes at a real moment in history (1990a). Thus, even when it spiritualizes, the rabbinic tradition does so entirely through the body. Spirit here is an aspect of body, almost, I would say, the same spirit that experiences the pleasure of sex through the body, and not something apart from, beyond or above the body.
Elliot Wolfson has gathered the rabbinic (and later) material connecting circumcision with vision of God:
It is written, “This, after my skin will have been peeled off, but from my flesh, I will see God” [Job 19:26]. Abraham said, after I circumcised myself many converts came to cleave to this sign. “But from my flesh, I will see God,” for had I not done this [circumcised myself], on what account would the Holy Blessed One, have appeared to me? “And the Lord appeared to him” [Genesis Rabbah 48:1, 479].
As Wolfson correctly observes there are two hermeneutic moves being made simultaneously in this midrash (1987b, 192–93). The first involves interpretation of the sequence in the Genesis text of Genesis 17:1–14, which is the description of Abraham's circumcision and Genesis 17:23 ff., which begins, “And The Lord appeared to Abraham in Elone Mamre.” The midrash, following its usual canons of interpretation, attributes strong causal nexus to these events following on one another. Had Abraham not circumcised himself, then God would not have appeared to him. This interpretation is splendidly confirmed by the Job verse. The Rabbis considered the Book of Job, together with the other Holy Writings, to be an exegetical text that has the function of interpreting (or guiding interpretation of) the Torah. In this case, the verse of Job, which refers to the peeling off of skin, is taken by a brilliant appropriation to refer to the peeling off of skin of circumcision, and the continuation of the verse, which speaks of seeing God from one's flesh, is taken as a reference to the theophany at Elone Mamre. The reading of sequence of the Torah's text is confirmed by the explicit causality which the Job text inscribes. Circumcision of the flesh—peeling of the skin—provides the vision of God. As Wolfson remarks, this midrash constitutes an interpretation of circumcision that directly counters the Pauline one: “The emphasis on Abraham's circumcision…can only be seen as a tacit rejection of the Christian position that circumcision of the flesh had been replaced by circumcision of the spirit (enacted in baptism)” (1987b, 194). The physical act of circumcision in the flesh, which prepares the (male) Jew for sexual intercourse, is also that which prepares him for Divine intercourse. It is hard, therefore, to escape the association of sexual and mystical experience in this text.
The strongly eroticized character of the experience of seeing God, established by the interpretation of circumcision, is made virtually explicit in another (later) midrashic text, Numbers Rabbah 12:10, also cited by Wolfson (1987b, 196–97):
O, Daughters of Zion, go forth, and gaze upon King Solomon, wearing the crown that his mother made for him on his wedding day, on his day of bliss [Song of Songs 3:11]: It speaks about the time when the Presence rested in the Tabernacle. “Go forth and gaze,” as it is said, “And all the people saw and shouted and fell on their faces” [Leviticus 9:24]. “The daughters of Zion,” those who were distinguished by circumcision, for if they were uncircumcised they would not have been able to look upon the Presence.…And thus it says, “Moses said: This is the thing which the Lord has commanded that you do, in order that the Glory of the Lord may appear to you” [Leviticus 9:6]. What was “this thing”? He told them about circumcision, for it says, “This is the thing which caused Joshua to perform circumcision” [Joshua 5:4].…
Therefore, Moses said to them, God commanded Abraham, your father, to perform circumcision when He wished to appear to him. So in your case, whoever is uncircumcised, let him go out and circumcise himself, “that the Glory of the Lord may appear to you” [Leviticus 9:6]. Thus Solomon said, “O Daughters of Zion, go forth and gaze upon King Solomon,” the King who desires those who are perfect, as it is written, “Walk before Me and be blameless” [Genesis 17:1], for the foreskin is a blemish upon the body.
This is indeed a remarkable text, not least for the blurring of gender which it encodes in its interpretative moves. Consistently with the entire midrashic enterprise of interpreting the Song of Songs, the verse in question is historicized as well. It is taken to refer to the event described in Leviticus 9, in which the entire People of Israel had a marvelous vision of God. This event is interpreted as a wedding between God and Israel, as are other moments of revelatory vision of God, such as the hierophany at Mount Sinai. The verse of Song of Songs that refers to King Solomon's wedding is taken, then, as an interpretation of the wedding day between God and Israel described in Leviticus. But complications begin. By a typical midrashic pun, King Solomon (Schelomo) is turned into God, the King who requires perfection (Schelemut). If the male partner is God, then the female partner must be Israel. Accordingly, the “Daughters of Zion” are Israel. However, this also results in a gender paradox, for many of the Israelites who participated in that Divine vision were men. Those very Daughters of Zion are accordingly understood as males. The word “Zion” (Hebrew Tsiyyon) is taken as a noun derived from the root ts/y/n, to be marked, and accordingly the Daughters of Tsiyyon are read as the circumcised men of Israel.
I would like to suggest that more than midrashic arbitrariness is at work here, for the mystical experience au fond, when experienced erotically, often involves (in the West?) gender paradox. The mystical experience is interpreted as a penetration by the Divine word or spirit into the body and soul of the adept. This is accordingly an image of sex in which the mystic is figured as the female partner. This paradoxical gender assignment (when the mystic is biologically male) is a problem for erotic mystic imagery (Eilberg-Schwartz 1991). Verna Harrison has described a similar issue in the work of Gregory of Nyssa:
When the human receptacle is described allegorically in terms of sexuality, it has to be represented as female. It is no accident that in his first work, On Virginity, and in one of his last, the great Commentary on the Song of Songs, Gregory chooses feminine language to speak of the human person, especially in describing our relations with God, which for him are the definitive aspect of human identity and existence.…In the treatise On Those Who Have Fallen Asleep, he speculates that in the resurrection human reproductive faculties may be transformed into a capacity to become impregnated with life from God and bring forth various forms of goodness from within oneself. This suggests that although human persons can be either male or female in this world and will be neither male nor female in the next (cf. Gal. 3.28), on a different level they all relate to God in a female way, as bride to Bridegroom. (Harrison 1992, 118–19)
My perhaps too bold suggestion is that our midrashic text is related to the same paradox of mystical experience. Circumcision is understood by the midrash text as feminizing the male, thus making him open to receive the Divine speech and vision of God. My interpretation of this midrash is that of medieval mystics (E. Wolfson 1987b, 198 ff.): “R. Yose said, Why is it written, ‘And the Lord will pass over the door [literally opening]’ [Exodus 12:23]?…‘Over the opening,’ read it literally as ‘opening'! That is, the opening of the body. And what is the opening of the body? That is the circumcision” (Zohar 2, 36a, cited in E. Wolfson [1987b, 204]). Although this text is a pseudepigraph of the thirteenth century, I am suggesting that the idea is already embryonic in the midrashic text, in which circumcised men are “daughters.” The mystic pseudepigraph would then be making explicit that which is implicit in the earlier formation. Thus, we have indeed evidence for the possibility of a Jewish (and Jewish Christian) view that regarded circumcision as necessary preparation for experiencing the Spirit. Note once more how that view is grounded precisely in the flesh. “From my flesh [my circumcised penis] I will see God.” Were such a view current among Paul's opponents in Galatia we would easily understand his charge, “Having begun in the spirit, are you now finishing up in the flesh?” 
The reason that this suggestion must be very tentative is that, as far as I know, the only evidence for such a doctrine is post-Pauline and therefore could very well be interpreted as a response to Paul. Nevertheless it remains very attractive to me to speculate that such a doctrine already existed among the “Jews” and thus the Judaeo-Christians, for then Paul's argument here has enormous force. “They are telling you that only the circumcised can see God, but you yourselves have already experienced visual experiences in the Holy Spirit, so their claim is shown to be a lie! Moreover, since the spirit is higher than the flesh, and you have already jumped (from the very beginning) to that level, will you now return to the lower level of the flesh?”  Another possibility is that Paul is simply contrasting two forms of initiation as such: the higher one, baptism, which is in the spirit, and the lower one, circumcision, which is in the flesh. It may even be that Paul's crucial flesh / spirit dyad is initially generated by this very opposition. In any case, it enters into a very rich texture of associations and meanings in his thought that go far beyond the moment. One way of saying this—and of seeing it—would be to understand this fundamental opposition as reproduced entirely at every moment in his discourse, as its foundational, structuring, generating “key” symbol.