1 Cor 10:1 For I do not want you to be unaware, brothers and sisters, that our fathers were all under the cloud and all passed through the sea, 10:2 and all were baptized into Moses in the cloud and in the sea, 10:3 and all ate the same spiritual food, 10:4 and all drank the same spiritual drink. For they were all drinking from the spiritual rock that followed them, and the rock was Christ.

Paul is thinking, in the first place, of the account in Ex 17, when God instructed Moses to strike the rock, and water came pouring forth.  Then there is a further instance of the divine provision of water, in Num 21:16-18.

Barrett comments that:

‘the references to the well of water in Num 20:11; 21:16 seem to have led to the belief (within Judaism) that the well (provided by the rock) accompanied Israel on their journeys.’

But what are we to make of Paul’s apparent agreement with the strange idea that the rock ‘accompanied’ the Israelites?  Did he actually believe this odd extra-biblical legend?

Peter Enns (The Bible Tells Me So, p16f) tells of his experience of hearing a Jewish professor comment on the OT story of the Israelites receiving water from the same rock at the beginning and end of their 40-year wilderness period, but in two different locations – Rephidim and Kadesh.  The professor noted that some ancient Jewish interpreters understood this as meaning that the water-producing rock was actually travelling with them.  Then, says Enns, the professor asked his students to turn to the present passage, and to note that Paul seems to inherit the same very odd idea.  For Enns, this constituted an ‘Aha’ moment in altering his view of biblical inspiration.

But Paul is not so much affirming the legend about how drinking water was provided during Israel’s wanderings, but rather affirming that Christ was present throughout that period.  Garland agrees that

‘Paul may have incorporated a traditional Jewish interpretation of the following rock, but he gives it a uniquely Christian twist: “The rock was Christ.” He is not thinking of a material rock following them, or a movable well, but of the divine source of the water that journeyed with them.’

Fee’s view is that

‘Paul seems to be referring to a common tradition of the continual supply of water; but his interest is not in the water but in its source, the rock, which he goes on to identify with Christ.’

Further:

‘That Paul now identifies the rock with Christ thus serves his double aim: (1) to emphasize the typological character of Israel’s experience, that it was by Christ himself that they were being nourished in the wilderness; and (2) thereby also to stress the continuity between Israel and the Corinthians, who by their idolatry are in the process of repeating Israel’s madness and thus are in danger of experiencing their judgment.’

Ciampa and Rosna (Commentary on the New Testament Use of the Old Testament) write:

‘Paul draws on a rich Jewish exegetical tradition (e.g., L.A.B. 10:7; 11:15; t. Sukkah 3:11, b. Šabb. 35a; b. Pesaḥ. 54a; Gen. Rab. 62:4; Num. Rab. 1:2; 9:14; 19:25–26; Tg. Onq. Num. 21:16–20) when he speaks in 10:4 of the rock that followed Israel (see Ellis 1978a; Enns 1996). In inquiring how the interpretive tradition of a moveable well developed, Enns (1996: 30) notes that “the miraculous provision of water in the desert is mentioned only at the beginning of the wilderness wandering period (Exod. 17, Rephidim; also the waters of Elim in Exod. 15:22–27; see Bib. Ant. 11:15 …) and at the end (Num. 20, Kadesh; Num. 21, Beer).” According to the exegetical tradition, the answer to the natural question of what the Israelites had done for water between those times was that “the rock of Exodus 17 and the rock of Numbers 20 are one and the same. Hence, this rock must have accompanied the Israelites through their journey.”

‘This interpretation was facilitated by a potential ambiguity in Num. 21:16–20. Jewish tradition came to understand God’s promise to provide Israel water from the well (21:16) to entail giving them not just water from the well, but the well itself. In the following verse the Israelites sing to the well, calling on it to spring up (or go up), using a verbal form that in every other context (Num. 21:17; 1 Sam. 25:35; Isa. 21:2; 40:9; Jer. 22:20; 46:11) entails movement from one place to another. The understanding that the well/rock traveled with Israel was based on an interpretation that Paul and his colleagues evidently inherited from their forebears. Paul’s use of the basic conclusion regarding the traveling nature of the rock should be distinguished from suggestions that he is indebted to the fuller (and fanciful) legends found in later rabbinic material. Garland (2003: 456–57) suggests that “Paul may have incorporated a traditional Jewish interpretation of the following rock, but he gives it a uniquely Christian twist: ‘The rock was Christ.’ He is not thinking of a material rock following them, or a movable well, but of the divine source of the water that journeyed with them. He understands the replenishing rock in a spiritual sense, not a physical sense.”’

Greg Beale notes that there are doubts about whether this Jewish tradition of a ‘moveable rock’ was present as early as the 1st century.  Even if it was (Beale argues), it is not at all clear that Paul adopts the tradition in 1 Cor 4.  The apostle:

‘may well be doing a biblical – theological exegesis of Exodus 14-17 in the light of Psalm 78:14-20 (e,g., “he splits the rocks . . . and gave them abundant drink . . . he struck the rock so that waters gushed out”) and 78:35 (“God was their rock”), the latter of which appears to identify God with the “rock” of Ps. 78:15-16, 20.’