Ashes are a sign of spiritual cleansing, as in the Rite of the Red Heifer (Numbers 19:17), in which the ashes of the calf, when mixed with water, had the ceremonial effect of purifying the sinner. In addition, for more than nineteen centuries the Christian believer’s Lenten journey has begun with a reminder of our mortality and a call to repentance through the placing of ashes on one’s head (Genesis 18:27, Job 42:6, Jeremiah 6:26, Matthew 11:21). This also explains why this season begins on a Wednesday. Since all regular Sunday worship services are an observance of Christ’s resurrection, and thus occasions for reverent joy, the Sundays during this period are not counted in the forty days of more somber remembrance of Christ’s Passion. The forty days are counted backward from Resurrection Sunday. Sinai at the giving of the law, Elijah’s fast on his way to the mountain of God, and Jesus’ forty-day fast at the beginning of His ministry, among others. The forty days are reminiscent of several biblical events: Moses’ stay on Mt. Lent is the Christian’s forty-day journey with the Lord to the cross and tomb, preparing for the joyous celebration of Christ’s Resurrection. The Wednesday before the first Sunday in Lent marks the beginning of this season of the Church Year. Here is a letter from a pastor talking the Imposition of Ashes at his church on Ash Wednesday I found this over on Intrepid Lutherans, the WELS blog.

Imposition of ashes liturgy u tube