The call to continuing conversion reflected in these readings is also the message of the ashes. We move through Lent from ashes to the baptismal font. We dirty our faces on Ash Wednesday and are cleansed in the waters of the font. More profoundly, we embrace the need to die to sin and selfishness at the beginning of Lent so that we can come to fuller life in the Risen One at Easter.
When we receive ashes on our foreheads, we remember who we are. We remember that we are creatures of the earth ("Remember that you are dust"). We remember that we are mortal beings ("and to dust you will return"). We remember that we are baptized. We remember that we are people on a journey of conversion ("Turn away from sin and be faithful to the gospel"). We remember that we are members of the body of Christ (and that smudge on our foreheads will proclaim that identity to others, too).
Renewing our sense of who we really are before God is the core of the Lenten experience. It is so easy to forget, and thus we fall into habits of sin, ways of thinking and living that are contrary to God's will. In this we are like the Ninevites in the story of Jonah. It was "their wickedness" that caused God to send Jonah to preach to them. Jonah resisted that mission and found himself in deep water. Rescued by a large fish, Jonah finally did God's bidding and began to preach in Nineveh. His preaching obviously fell on open ears and hearts, for in one day he prompted the conversion of the whole city.
From the very beginning of Lent, God's word calls us to conversion. If we open our ears and hearts to that word, we will be like the Ninevites not only in their sinfulness but also in their conversion to the Lord. That, simply put, is the point of Ash Wednesday!