31 And the mouth of it within the chapiter and above was a cubit: but the mouth thereof was round after the work of the base, a cubit and an half: and also upon the mouth of it were gravings with their borders, foursquare, not round.
The mouth of the laver was one cubit on account of the unity of confession and faith because we are all baptized in the confession of the Father and the Son and the Holy Spirit, as the apostle says: “One Lord, one faith, one baptism, one God and Father of all.” And the mouth itself was at the top of the capital57 to teach that the way to the heavenly kingdom had been opened to us through baptism. But the actual laver was a cubit and a half in size, in view, no doubt, of the perfection of good works and the beginning of contemplation. For the whole cubit in the laver denotes the perfection of good works.
[AD 735] Bede on 1 Kings 7:31-32