Now there were six water pots of stone set there after the Jews' manner of purifying, containing two or three metretes{2 to 3 metretes is about 20 to 30 U. S. Gallons, 16 to 25 imperial gallons, or 75 to 115 litres.} apiece.
Now, John was, by physical birth, a cousin to Jesus. However, John was born before Jesus was born. Probably in about the sixth month of Mary's pregnancy when John was born. Yet, John is saying of Him, "He is preferred before me: for He was before me." So, he is talking about that pre-existence of Jesus prior to His incarnation.