SPIRITUAL ROCK (πνευματική πέτρα, spiritual rock). This expression occurs only in 1 Corinthians 10:4: “They drank of that spiritual Rock that followed them: and that Rock was Christ” (KJV). As may be ascertained from the adjective “spiritual,” as well as from the following identification, “rock” is used metaphorically, or typically (of Christ). “Spiritual,” at least in this particular usage, seems to be virtually equivalent to “invisible,” “supernatural,” “divine,” referring to the source of the water. Theirs was a supernatural sustenance. In employing this figure, Paul is also identifying the OT Rock of Israel (Yahweh) with Christ. Robertson has an excellent comment on the statement, “They drank of that spiritual Rock that followed them”:

Change to the imperfect epinon shows their continual access to the supernatural source of supply. The Israelites were blessed by the water from the rock that Moses smote at Rephidim (Exod 17:6) and at Kadesh (Num 20:11) and by the well of Beer (21:16). The rabbis had a legend that the water actually followed the Israelites for forty years in one form a fragment of rock fifteen feet high that followed the people and gushed out water. Baur and some other scholars think that Paul adopts this “Rabbinical legend that the water-bearing Rephidim rock journeyed onwards with the Israelites” (Findlay). That is hard to believe, though it is quite possible that Paul alludes to this fancy and gives it a spiritual turn as a type of Christ in allegorical fashion. Paul knew the views of the rabbis and made use of allegory on occasion (Gal 4:24) (A. T. Robertson, Word Pictures in the New Testament, IV, 151, 152).

Of “that Rock was Christ” he writes:

He definitely states here in symbolic form the prëexistence of Christ. But surely “we must not disgrace Paul by making him say that the pre-incarnate Christ followed the march of Israel in the shape of a lump of rock” (Hofmann). He does mean that Christ was the source of the water which saved the Israelites from perishing (Robertson and Plummer) as he is the source of supply for us today (ibid., p. 152).