When the Homily is about Immunology

Gotta love the Desert Fathers...

Two old men had lived together in the desert for many years and had
never quarreled. The first said to the other, "Let us also have a fight
like other men do." The other replied, "I do not know how to fight."
The first said to him, "Look, I will put a brick between us, and I will
say it is mine, and you say, `No, it is mine,' and so the fight will
begin." So they put a brick between them and the first said, "This
brick is mine," and the other said, "No, it is mine," and the first
responded, "If it is yours, take it and go" - so they gave it up without
being able to find an occasion for an argument.

Sayings of the Desert Fathers