Bede, on 1Kgs 7:38

“He made also ten lavers of brass: one laver contained four bases, and was of four cubits: and upon every base, in all ten, he put as many lavers.”

“The number forty conventionally typifies great perfection because, of course, four tens make forty; now there are ten precepts whereby our whole code of conduct is laid down in the divine law, but four books of the Gospels in which entry into our heavenly homeland was opened to us through the plan of the Lord's incarnation. And because all who are involved in the ministry of sacred baptism must, together with the faith and mysteries of the gospel, show the fruits of upright conduct, it is fitting that each of the lavers in which the whole burnt offerings were washed should hold forty baths.”

Imported from an open dataset — not yet checked against the printed edition.