1 Corinthians 10:4

For they drank of a spiritual rock that followed them (epinon ek pneumatikh akolouqoush petra). 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 ( Exodus 17:6 ) and at Kadesh ( Numbers 20:11 ) and by the well of Beer ( Numbers 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 ( Galatians 4:24 ). And the rock was Christ (h petra de hn o Cristo). He definitely states here in symbolic form the preexistence 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.