Ashes

"The symbolism of bodily marking can be found throughout the Bible.

Cain receives a mark to warn others not to lay hands on this first murderer (Gen. 4:15).

Slaves are marked as a badge of ownership (Exod. 21:6).

In the book of Ezekiel, a heavenly messenger is commanded to place a mark on the foreheads of the righteous (Ezek. 9:4).

The followers of Antichrist receive a mark of their own, on their foreheads and hands (Rev. 14:9).

The forehead ashes received by Christians at the beginning of Lent are an ancient symbol of penance and sorrow. They might also be usefully thought of as a kind of brand or marking, signifying that even in an age that worships above all things the 'freedom to choose,' the Christian is not his own. He is a servant, bought and paid for by a Master to whom he will answer for how he has used whatever freedom he has in this world."

I believe there is only true freedom when we finally obey and trust God. (Soutenus)

post source — Edward Feser, the author of The Last Superstition: A Refutation of the New Atheism.