22 Noah's ark was a type of the Church, as the Apostle Peter says— “In Noah's ark few, that is, eight souls, were saved through water: which also after a true likeness does now save us, even baptism.” As in the ark there were all kinds of animals, so also in the Church there are men of all races and characters. As in the one there was the leopard with the kids, the wolf with the lambs, so in the other there are found the righteous and sinners, that is, vessels of gold and silver with those of wood and of earth.
The ark had its rooms: the Church has many mansions. Eight souls were saved in Noah's ark. And Ecclesiastes bids us “give a portion to seven yea, even unto eight,” that is to believe both Testaments. This is why some psalms bear the inscription for the octave, and why the one hundred and nineteenth psalm is divided into portions of eight verses each beginning with its own letter for the instruction of the righteous. The beatitudes which our Lord spoke to his disciples on the mountain, thereby delineating the Church, are eight.
And Ezekiel for the building of the temple employs the number eight. And you will find many other things expressed in the same way in the Scriptures. The raven also is sent forth from the ark but does not return, and afterwards the dove announces peace to the earth. So also in the Church's baptism, that most unclean bird the devil is expelled, and the dove of the Holy Spirit announces peace to our earth. The construction of the ark was such that it began with being thirty cubits broad and gradually narrowed to one.
Similarly the Church, consisting of many grades, ends in deacons, presbyters, and bishops. The ark was in peril in the flood, the Church is in peril in the world. When Noah left the ark he planted a vineyard, drank thereof, and was drunken. Christ also, born in the flesh, planted the Church and suffered. The elder son made sport of his father's nakedness, the younger covered it: and the Jews mocked God crucified, the Gentiles honoured Him. The daylight would fail me if I were to explain all the mysteries of the ark and compare them with the Church.
Who are the eagles among us? Who the doves and lions, who the stags, who the worms and serpents? So far as our subject requires I will briefly show you. It is not the sheep only who abide in the Church, nor do clean birds only fly to and fro there; but amid the grain other seed is sown, “amidst the neat grain-fields burrs and caltrops and barren oats lord it in the land.” What is the husbandman to do? Root up the darnel? In that case the whole harvest is destroyed along with it.
Every day the farmer diligently drives the birds away with strange noises, or frightens them with scarecrows: here he cracks a whip, there he spreads out some other object to terrify them. Nevertheless he suffers from the raids of nimble roes or the wantonness of the wild asses; here the mice convey the grain to their garners underground, there the ants crowd thickly in and ravage the grain-field. Thus the case stands. No one who has land is free from care. While the householder slept the enemy sowed tares among the wheat, and when the servants proposed to go and root them up the master forbade them, reserving for himself the separation of the chaff and the grain.
There are vessels of wrath and of mercy which the Apostle speaks of in the house of God. The day then will come when the storehouses of the Church shall be opened and the Lord will bring forth the vessels of wrath; and, as they depart, the saints will say, “They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us.” No one can take to himself the prerogative of Christ, no one before the day of judgment can pass judgment upon men. If the Church is already cleansed, what shall we reserve for the Lord? “There is a way which seems right unto a man, but the end thereof are the ways of death.” When our judgment is so prone to error, upon whose opinion can we rely?
Source: The Dialogue Against the Luciferians (New Advent)