6 However, to seek the mystery of the deed in the figure, who are they that sell oxen? Who are they that sell sheep and doves? They are they who seek their own in the Church, not the things which are Christ's. They account all a matter of sale, while they will not be redeemed: they have no wish to be bought, and yet they wish to sell. Yes; good indeed is it for them that they may be redeemed by the blood of Christ, that they may come to the peace of Christ. Now, what does it profit to acquire in this world any temporal and transitory thing whatsoever, be it money, or pleasure of the palate, or honor that consists in the praise of men?
Are they not all wind and smoke? Do they not all pass by and flee away? Are they not all as a river rushing headlong into the sea? And woe to him who shall fall into it, for he shall be swept into the sea. Therefore ought we to curb all our affections from such desires. My brethren, they that seek such things are they that sell. For that Simon too, wished to buy the Holy Ghost, just because he meant to sell the Holy Ghost; and he thought the apostles to be just such traders as they whom the Lord cast out of the temple with a scourge.
For such an one he was himself, and desired to buy what he might sell: he was of those who sell doves. Now it was in a dove that the Holy Ghost appeared. Who, then, are they, brethren, that sell doves, but they who say, “We give the Holy Ghost”? But why do they say this, and at what price do they sell? At the price of honor to themselves. They receive as the price, temporal seats of honor, that they may be seen to be sellers of doves. Let them beware of the scourge of small cords.
The dove is not for sale: it is given freely; for grace, or favor, it is called. Therefore, my brethren, just as you see them that sell, common chapmen, each cries up what he sells: how many stalls they have set up! Primianus has a stall at Carthage, Maximianus has another, Rogatus has another in Mauritania, they have another in Numidia, this party and that, which it is not in our power now to name. Accordingly,one goes round to buy the dove, and everyone at his own stall cries up what he sells.
Let the heart of such an one turn away from every seller; let him come where he receives freely. Aye, brethren, and they do not blush, that, by these bitter and malicious dissensions of theirs, they have made of themselves so many parties, while they assume to be what they are not, while they are lifted up, thinking themselves to be something when they are nothing. But what is fulfilled in them, since that they will not be corrected, but that which you have heard in the psalm: “They were rent asunder, and felt no remorse”?
Source: Tractates on the Gospel of John (New Advent)