Ash Wednesday is the name of the day that marks the beginning of the season of Lent. Ash Wednesday became a part of the Church's public worship somewhere between the 8th and 10th centuries. As early as the 2nd century, those who desired to baptism and admission to the Lord' Supper and those who had been baptized but were under church discipline, began a 40 day period of penance that culminated on Easter Eve with baptism and (re)admission to the Supper. This practice fell out of use between the 8th and 10th centuries when the church-at-large took up the practice annually for itself.
The 40 day time period is the Church's way of participating in the great challenges with sin and mortality that have taken place in the Scriptures in the course of 40 days.
The ashes represent our human frailty and mortality which is the consequence of our sin and disobedience of God and our complete dependence upon God's grace and mercy. Ashes upon the head is the expression of repentance and grief throughout the Old Testament and into the New. See Esther 4:1; Job 42:6; Isaiah 58:5; Jeremiah 6:26; Daniel 9:3; Jonah 3:6; Matthew 11:21.
The season of Lent begins on Wednesday, February 6th, with Ash Wednesday. The mark of ashes remind us that we are from dust and to dust we shall return. It wasn't what God had in His mind when He made us, but this is what happens when think they know better than God. Thankfully, ashes are not the only mark we bear. In Holy Baptism, we have been marked with the sign of the cross. The cross marks us as one redeemed by Christ the Crucified. The ashes will wash off but the mark of the cross is indelible. Your sins have been washed away, your dead body will be raised to new life and you will not die but live.
The season of Lent is a special time for remembering who we are by nature through sin and who we are by the grace through faith. We sometimes have the idea that Lent is a sad time. Not so! It is a time of eager anticipation for the joy that lies ahead in the resurrection of Jesus Christ.
The focus of Lent is really no different than for any of the other seasons of the Church's year. Sin and Grace. Confession and Absolution. Repentance and Faith. Law and Gospel. Maybe it's the urgency of the approaching Holy Week and Easter that give this season it's special intensity of attention to prayer and preparation.
The season of Lent lasts forty days, the same time Moses was on the mountain receiving the Law from God and Jesus was in the desert being tempted by Satan. During these 40 days of Lent, we are reminded that Jesus kept the law for us and defeated Satan, and all to wash the ashes off of us and imprint His precious Name upon us.