1 Corinthians 4:10
May I mention another thing yet more ridiculous than this? Only let no one tax us with speaking out of season, should our argument proceed with that instance also. For he that would cleanse an ulcer will not hesitate first to pollute his own hands. What then is this so very ridiculous custom? It is counted indeed as nothing; (and this is why I grieve;) but it is the beginning of folly and madness in the extreme. The women in the bath, nurses and waiting-maids, take up mud and smearing it with the finger make a mark on the child's forehead; and if one ask, What means the mud, and the clay? The answer is, “It turns away an evil eye, witchcraft and envy.” Astonishing! What power in the mud! What might in the clay! What mighty force is this which it has? It averts all the host of the devil. Tell me, can you help hiding yourselves for shame? Will you never come to understand the snares of the devil, how from earliest life he gradually brings in the several evils which he has devised? For if the mud has this effect, why do you not yourself also do the same to your own forehead, when you are a man and your character is formed; and you are likelier than the child to have such as envy you? Why do you not as well bemire the whole body? I say, if on the forehead its virtue be so great, why not anoint yourself all over with mud? All this is mirth and stage-play to Satan, not mockery only but hell-fire being the consummation to which these deceived ones are tending.
14. Now that among Greeks such things should be done is no wonder: but among the worshippers of the Cross, (τὸν σταυρὸν προσκυνοῦσι) and partakers in unspeakable mysteries, and professors of such high morality, (τοσαῦτα φιλοσοφοῦσιν) that such unseemliness should prevail, this is especially to be deplored again and again. God has honored you with spiritual anointing; and do you defile your child with mud? God has honored you, and do you dishonor yourself? And when you should inscribe on his forehead the Cross which affords invincible security; do you forego this, and cast yourself into the madness of Satan?
If any look on these things as trifles, let them know that they are the source of great evils; and that not even unto Paul did it seem right to overlook the lesser things. For, tell me, what can be less than a man's covering his head? Yet observe how great a matter he makes of this and with how great earnestness he forbids it; saying, among many things, “He dishonors his head.” Now if he that covers himself “dishonors his head”; he that besmears his child with mud, how can it be less than making it abominable? For how, I want to know, can he bring it to the hands of the priest? How can you require that on that forehead the seal should be placed by the hand of the presbyter, where you have been smearing the mud? Nay, my brethren, do not these things, but from earliest life encompass them with spiritual armor and instruct them to seal the forehead with the hand (τῇ χειρὶ παιδεύτε σφραγίζειν τὸ μέτωπον): and before they are able to do this with their own hand, do you imprint upon them the Cross.
Why should one speak of the other satanical observances in the case of travail-pangs and childbirths, which the midwives introduce with a mischief on their own heads? Of the outcries which take place at each person's death, and when he is carried to his burial; the irrational wailings, the folly enacted at the funerals; the zeal about men's monuments; the importunate and ridiculous swarm of the mourning women; the observances of days; the days, I mean, of entrance into the world and of departure?
15. Are these then, I beseech you, the persons whose good opinion you follow after? And what can it be but the extreme of folly to seek earnestly the praise of men, so corrupt in their ideas, men whose conduct is all at random? When we ought always to resort to the unsleeping Eye, and look to His sentence in all that we do and speak? For these, even if they approve, will have no power to profit us. But He, should He accept our doings, will both here make us glorious, and in the future day will impart to us of the unspeakable good things: which may it be the lot of us all to obtain, through the grace and loving-kindness of our Lord Jesus Christ; with Whom to the Father and the Holy Spirit be glory, power, honor, now and always, and unto everlasting ages. Amen.
Source: Homilies on First Corinthians (New Advent)