Ash Wednesday is a somber day in the liturgical calendar as it commemorates the beginning of Lent, foreshadowing what will occur at the end of the 40 days.
In a homily on Ash Wednesday in 1980, St. John Paul II went so far as to call it a, "liturgy of death":
The first day of Lent indicates the way of this conversion in its fullest dimension. First of all, therefore, this is the return to the "principle." The Church invites each of us to stand before the liturgy today, which dates back to the very threshold of human history: "Remember that you are dust and dust you will return "(Gen 3.19). These are the words of the book of Genesis; in them we find the simplest expression of that "liturgy of death", of which man has become a participant as a consequence of sin.
More specifically St. John Paul II is referring to the imposition of ashes and how they remind us of our mortality:
Today's "liturgy of death" which is expressed in the rite of the imposition of ashes, unites, in a certain sense, this first day of Lent to the last day, the day of Good Friday, the day of Christ's death on the cross.
St. John Paul II explains how, "The way, therefore, passes through Good Friday. Go through the cross. There is no other way of full "conversion."
In order to participate in the "liturgy of the resurrection," St. John Paul II reminds us that we must first pass through Good Friday.
Lent is a time when we experience that death, death to self and to our personal attachments.
By going through this type of death, we unite ourselves to Jesus on the cross, uniting our sufferings to his. Then we can participate in the joys of the resurrection and the fruits of God's grace.