Your glorying is not good. Know you not that a little leaven leavens the whole lump? Purge out therefore the old leaven, that you may be a new lump, as you are unleavened. For indeed Christ our Passover is sacrificed for us: therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth. (1 Cor. 5:6-8)
Why do we "celebrate the feast" of Christ's sacrifice at Mass with unleavened bread? It's not simply because the Jews ate unleavened bread as part of the Passover to celebrate their deliverance in haste from Egypt, but also because to be "unleavened" means not to be infected with the corrupting yeast of "malice and wickedness", or the "leaven of the Pharisees", which is hypocrisy.
Since the Fall of Man, all of us have been born with this infection. If we let it, it "leavens the whole lump".
Anthony Esolen makes this clear in a stunning and disturbing article in Crisis Magazine. He quotes a young man who has written an advice column for other young men, giving them tips on how to convince their girlfriends to get an abortion when the girlfriend gets pregnant and resists the idea.
You need to bring up the subject of abortion with every ounce of verbal finesse and situation-appropriate sensitivity. You should sound as sincere as possible and tell her that you want her to be the mother of your children one day, but that now is not the right time to start a family. Explain you want to wait until you are further along in your career/life goals and you can afford to give your future family all the comforts of life you cannot deliver today. Finally, explain if she has the abortion now, you will be able to plan your lives together so that everything is perfect. Then, after she agrees and has the abortion, dump her. It’s called a “hail mary” in part because of its difficulty to execute, so if you stay with her post-abortion and she becomes pregnant again you’re really f*****.
Esolen comments ...
The writer recommends shameless lying. Is that a surprise? Isn’t fornication itself, even for the mildest of people, all tangled up in evasions, demurrals, half-promises, and lies? The writer uses girls for his pleasure, but despises them. They are his toys, and when you’re sick of a toy, you throw it away. Is that a surprise? And if the perfectly predictable result of the child-making thing occurs, and they make a child, his one thought is how to persuade her to throw it away, too. Why not? It is an accident (a piano falling upon your head from the tenth story of a tenement, that is an accident; begetting a child by the child-making thing is not), or it is s*** (which must be disposed of). No care for her sorrow or her health; no care for the child; no moral qualms at all.
When we find someone loudly affirming the goodness of something wicked, our first step should not be to try to persuade him otherwise. That would be to aim at but one tentacle of the cancer. The treatment must reach much farther down to the roots. But for the sake of everyone else within earshot, and for our own sanity, we should look to the nearby organs. You defend pornography, do you? Then be honest. Do you not also defend legal prostitution? Group sex, or any sexual escapades among consenting adults? Polygamy, for those who want it? Sexual experimentation among teenagers, so long as it makes a pretense of epidermal hygiene? Easy divorce? Abortion?
Jack Kevorkian did not only affirm the goodness of suicide. He was himself a murderer. His paintings were sufficient to lead any sane person to conclude that he was profoundly evil, or mentally deranged, or both—for evil is itself a derangement. The media could have sunk him into the public’s contempt if they had only publicized those paintings, or probed the other cancerous organs in that man’s moral psyche. They did not. They chose instead to bracket the one cause, assisted suicide, and ignore everything else. That plays into the devil’s hands.
We must not do so.
In other words, we must keep the feast "not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth". For a little leaven leavens the whole lump, and the cancer of sin and selfishness spreads to every part of the body.
What does this have to do with the Immaculate Conception?
Mary is, from the moment her life begins, unleavened. She is as we were all designed to be, the "unleavened bread of sincerity and truth". She is granted that grace from the moment of her conception by virtue of Christ's then-future sacrifice - and though we (who have not experienced that extraordinary grace) must struggle to "purge out the old leaven" so that we may "become a new lump", she shows us what, as disciples, we may become.
For purity is productive. Faithfulness is fertile. Cleanliness conceives.
If we become as unleavened bread, then the leaven of the Kingdom can begin to work in us.
If we remain as we are, the cancer will spread and we are doomed.