Just to add a description of the pool itself.
There were two large basins: the northern pool, measuring 53 x 40 meters, which served as a reservoir (or
otṣar) for collected rainwater, and the southern pool (47 x 52 meters) which served as the ritual pool (
miqveh). The two pools would have been surrounded by galleries or porticoes on all four sides, with an additional portico extending across the massive 6-meter barrier wall separating the two basins (cf. John 5:2 “Now there is in Jerusalem by the sheep gate a pool, which is called in Hebrew Bethesda, having five porticoes”).
Within the massive barrier wall, there was a vertical shaft which led to a horizontal tunnel with a sluice gate at the bottom, which meant that the water of the
otṣar to the north could easily have come into contact with with the water of the
miqveh to the south by simply lifting the sluice gate. Further on, at the lower level of the tunnel, there was a covered trough in which more than 1 cubic meter of valid water could have ‘mingled’ with the added water, before then rising and replenishing the waters of the southern pool. A sluice gate was opened at the far end of this trough when necessary, which then, in turn, led to a covered channel that helped drain surplus water away to the south.
The north pool, a dam or reservoir for rain water, and the sluice gate is thought to have already existed by the 8th century BC, before the Exile; the channel at this time brought a steady stream of water from the reservoir into the city. By the early 2nd century BC, the bigger southern pool was constructed and the channel was enclosed.
A flight of steps facilitated access down to the very base of the pool, depending on the amount of water available there for bathing. These extended down along the entire western side of the southern pool (53 meters in length), with sets of steps in groups of one to six extending between landings. The landings at different intervals would have been used for the placing of the beds of disabled people.
It is thought that the pool would have bubbled and frothed when the water was drained into the southern pool, which was what John was describing when the waters were “stirred up.”* In addition, layers of bright red soil trapped between geological layers, seen within the lower part of this area, may have contributed to the picture provided by early Christian writers such as Eusebius and Eucherius regarding the color of the stirred-up waters (Eusebius describes it as “of a ruddy color,” while Eucherius calls it “reddish”).
- The thing is, many scholars think that the verse was not authentic, but could have been added by a scribe (who probably did not have any knowledge of the mechanics of the actual pool) who either tried to explain how the water was stirred or who recorded a popular belief about the water. There’s of course the fact that many early surviving manuscripts of John don’t have this portion, but also: (1) the verse has a vocabulary and syntax that is un-Johannine (i.e. it is not in keeping with the vocabulary and syntax of the rest of the Gospel); (2) several of the manuscripts that include the verses mark them with an asterisk or obelisk as if to mark it as spurious; and because there is a great amount of textual diversity among the witnesses that do include the verses. (In other words, the actual form of the verses differ across the manuscripts - you’d expect a little more consistency in the words if it was authentic.)
