Q: Why do Catholics have their foreheads signed with ashes in the form of a cross on Ash Wednesday?

A: Because in the Bible a mark on the forehead is a symbol of a person’s ownership. By having their foreheads marked with the sign of a cross, this symbolizes that the person belongs to Jesus Christ, who died on a Cross.

This is in imitation of the spiritual mark or seal that is put on a Christian in baptism, when he is delivered from slavery to sin and the devil and made a slave of righteousness and Christ (Rom. 6:3-18).

It is also in imitation of the way the righteousness are described in the book of Revelation, where we read of the servants of God (the Christian faithful, as symbolized by the 144,000 male virgins):

“Do not harm the earth or the sea or the trees, till we have sealed the servants of our God upon their foreheads.” (Revelation 7:3)

“[The demon locust] were told not to harm the grass of the earth or any green growth or any tree, but only those of mankind who have not the seal of God upon their foreheads” (Revelation 9:4)

“Then I looked, and lo, on Mount Zion stood the Lamb, and with him a hundred and forty-four thousand who had his name and his Father’s name written on their foreheads.” (Revelation 14:1)

This is in contrast to the followers of the beast, who have the number 666 on their foreheads or hands.

The reference to the sealing of the servants of God for their protection in Revelation is an allusion to a parallel passage in Ezekiel, where Ezekiel also sees a sealing of the servants of God for their protection:

“And the LORD said to him [one of the four cherubim], ‘Go through the city, through Jerusalem, and put a mark [literally, “a tav”] upon the foreheads of the men who sigh and groan over all the abominations that are committed in it.’ And to the others he said in my hearing, ‘Pass through the city after him, and smite; your eye shall not spare, and you shall show no pity; slay old men outright, young men and maidens, little children and women, but touch no one upon whom is the mark. And begin at my sanctuary.’ So they began with the elders who were before the house.” (Ezekiel 9:4-6)

Unfortunately, like most modern translations, the one quoted above (the Revised Standard Version, which we have been quoting thus far), is not sufficiently literal. What it actually says is to place a tav on the foreheads of the righteous inhabitants of Jerusalem. Tav is one of the letters of the Hebrew alphabet, and in ancient script it looked like the Greek letter chi, which happens to be two crossed lines (like an “x”) and which happens to be the first letter in the word “Christ” in Greek (christos). The Jewish rabbis commented on the connection between tav and chi and this is undoubtedly the mark Revelation has in mind when the servants of God are sealed in it.

The early Church Fathers seized on this tav-chi-cross-christos connection and expounded it in their homilies, seeing in Ezekiel a prophetic foreshadowing of the sealing of Christians as servants of Christ. It is also part of the background to the Catholic practice of making the sign of the cross, which in the early centuries (as can be documented from the second century on) was practiced by using one’s thumb to furrow one’s brow with a small sign of the cross, like Catholic do today at the reading of the Gospel during Mass.

The sign is done with ashes because ashes are a biblical symbol of mourning and penance. In Bible times the custom was to fast, wear sackcloth, sit in dust and ashes, and put dust and ashes on one’s head. While we no longer normally wear sackcloth or sit in dust and ashes, the customs of fasting and putting ashes on one’s forehead as a sign of mourning and penance have survived to this day. These are two of the key distinctives of Lent.

“That same day a Benjamite ran from the battle line and went to Shiloh, his clothes torn and dust on his head.” (1 Samuel 4:12)

“On the third day a man arrived from Saul’s camp, with his clothes torn and with dust on his head. When he came to David, he fell to the ground to pay him honor.” (2 Samuel 1:20

“Tamar put ashes on her head and tore the ornamented robe she was wearing. She put her hand on her head and went away, weeping aloud as she went.” (2 Samuel 13:19)

“When David arrived at the summit, where people used to worship God, Hushai the Arkite was there to meet him, his robe torn and dust on his head.” (2 Samuel 15:32)

The ashes also symbolize death and so remind us of our mortality. Thus when the priest uses his thumb to sign one of the faithful with the ashes, he says, “Remember, man, that thou art dust and unto dust thou shalt return,” which is modeled after God’s address to Adam (Genesis 3:19; cf. Job 34:15, Psalms 90:3, 104:29, Ecclesiastes 3:20). This also echoes the words at a burial, “Ashes to ashes; dust to dust,” which is based on God’s words to Adam in Genesis 3 and Abraham’s confession, “I am nothing but dust and ashes” (Genesis 18:27). It is thus a reminder of our mortality and our need to repent before this life is over and we face our Judge.