Ash Wednesday

In Western Christianity, Ash Wednesday marks the first day, or the start of the season of Lent, which begins 40 days prior to Easter (Sundays are not included in the count).
Lent is a time when many Christians prepare for Easter by observing a period of fasting, repentance, moderation and spiritual discipline. During some Ash Wednesday services, the minister will lightly rub the sign of the cross with ashes onto the foreheads of worshipers.
Not all Christian churches observe Ash Wednesday or Lent. They are mostly observed by the Lutheran, Methodist, Presbyterian and Anglican denominations, and also by Roman Catholics. Eastern Orthodox churches observe Lent or Great Lent, during the 6 weeks or 40 days preceding Palm Sunday with fasting continuing during the Holy Week of Easter. Lent for Eastern Orthodox churches begins on Monday and Ash Wednesday is not observed.
The Bible does not mention Ash Wednesday or the custom of Lent, however, the practice of repentance and mourning in ashes is found in 2 Samuel 13:19; Esther 4:1; Job 2:8; Daniel 9:3; and Matthew 11:21.