So we can truly say there were vast quantities of water before the Most Holy, the Mercy seat, the throne of God, “like the sea in abundance” (Ecclesiasticus 50:3). This fact was used in visions recorded in Revelation, the use of imagery drawn from the earthly Jerusalem in order to describe the heavenly, and also reproduces some of the features of Ezekiel’s vision of the holy waters (see Rev.22:1,2,14; 4:6; NIV).
One cistern occupies part of the SE corner below the Temple itself and lines up with the Foundation Cornerstone at the SE corner of the Temple platform. This cistern is of importance and is of a curious cruciform shape, it has the shape of a cross, and is called the Cross Cavern. It contains a long passage running in the direction of the Most Holy, under which there is a natural cavern. Over the Cross Cavern stood the Altar of Burnt Offering, connected by what was called the Blood Passage to the cavern under the Most Holy. In other words sacrificial blood coursed its way underground from the Altar, passed the Most Holy, and then on out of sight. It is Jesus laying down His life, entering the Heavenly and presenting His sacrifice to His Father (Heb.9:12-24).
According to the account given in the Talmud there was another channel for the offal of the sacrifices, so that by means of sluices of water, all the unwanted parts of offerings were carried off through subterranean passages, to be completely hidden from sight. It has also been discovered that water still flows under the site of the Most Holy with water from the Gihon Spring, a stream of clear water is still issuing under the Temple Hill. The Spring is also not dependent on rain, or drought, it never, ever dries up. It is perennial, ever flowing. In fact it has been witnessed to rise in level during drought. Twenty-five feet below the valley surface it is still flowing, a fitting symbol of Him who imparts everlasting, never-ending waters of life. It is also interesting to note that one of the Rivers that issued from the Garden of Eden which faced East, was also called the River Gihon (Gen.2:10,13). The Temple itself was positioned facing East, like the Garden of Eden, East from where the Spring issued, and facing the rising of the sun, for God and Christ are the Light and the Life of the world.