Ashes signify man's overthrow by time. Our own swift passage, ours and not someone else's, ours, mine. When at the beginning of Lent the priest takes the burnt residue of the green branches of the last Palm Sunday and inscribes with it on my forehead the sign of the cross, it is to remind me of my death.
Memento homo
quia pulvis
est et in pulverem reverteris.
Everything turns to ashes, everything whatever. This house I live in, these clothes I am wearing, my household stuff, my money, my fields, meadows, woods, the dog that follows me, my horse in his stall, this hand I am writing with, these eyes that read what I write, all the rest of my body, people I have loved, people I have hated, or been afraid of, whatever was great in my eyes upon earth, whatever small and contemptible, all without exception will fall back into dust.----Romano GUARDINI, Sacred Signs.
Our annual observance of Lent begins with the sign of the ashes pressed upon the warm flesh of our forehead, as a fitting reminder of our mortality. The rough feel of the burnt remains of what was once green and alive reminds us of our mortal fate, of the road that all men without exemption, no matter how influential or great, will have to take, a road that leads to death. Death entered into creation thanks to man's option--freely made--to go away from God. This option in man has been observable: to move away in an effort to assert his own independence from God, a mistaken effort. Lent shows us another path: one which leads to authentic freedom and fullness of life.
This is why Lent culminates in the celebration of the Paschal Triduum, at the climax of which is another sign: water, an element which harbors within itself the force necessary to destroy evil, to cleanse, reinvigorate, give life. The path begun by Ash Wednesday begins with the reminder of our mortality, so as to end with a celebration of life and light. This is why Lent isn't exactly a somber season; rather, it is characterized by joy and hope in the Christian struggle for inner renewal in Christ. In the liturgy there is sense in calling Lent a joyful season, there is sense in talking about "the glory of these forty days".