The bronze work that Hiram did continues with the construction of the sea
and the casting of the oxen upon whose backs it stood. The sea of bronze was very large; one commentator likens it to the casting of the largest of church bells. It was circular in shape. The measurements given, when we convert them into contemporary units, are a diameter of 5 to 6 metres, a height of roughly 2.5 metres, and a circumference of roughly 15 to 16 metres. The volume was about 45,000 litres (10,000 imperial gallons).
If there is a spiritual significance to the twelve bronze-cast oxen, it is not apparent. Oxen were commonly used as beasts of burden and as such they were fitted to be represented as bearing the sea.
The use they would put to the sea was ritual washings. This included the washing of the priests and the slaughtered animal sacrifices that were brought. We ought to remember that to the pious Israelite, these washings were not primarily hygienically motivated. The cleansing intended was a ritual cleansing rather. The brazen sea was the temple’s counterpart of the basin
of the tabernacle that was placed between the tent itself and the altar of burnt offerings (Exodus 30:18).
23 Then he made the sea of cast metal. It was round, ten cubits from brim to brim, and five cubits high, and a line of thirty cubits measured its circumference.