He is trekking 1000km to Santiago de Compostela to expiate unknown sins.
From the guardian.co.uk
She could not apologize enough, expiate enough, or be contrite enough about OBL's actions.
From the economist.com
Perhaps to expiate all that shame, he bypassed university and became a policeman in Burma.
From the time.com
These authors are used as scapegoats to expiate the culture's sins, its reality hunger.
From the latimes.com
Religious scriptures were chanted at the funeral ceremony to expiate the sins of the dead.
From the en.wikipedia.org
All this does not expiate China from its environmental sins.
From the newscientist.com
It is believed that all the gods come in human form to take a dip at the sangam and expiate their sins.
From the en.wikipedia.org
Find some other way to expiate your guilt.
From the delawareonline.com
In his later years, he showed a wounded vulnerability and a desire to understand and expiate the Vietnam mistake.
From the washingtonpost.com
More examples
Make amends for; "expiate one's sins"
(expiation) atonement: compensation for a wrong; "we were unable to get satisfaction from the local store"
(expiation) the act of atoning for sin or wrongdoing (especially appeasing a deity)
(Expiation) In Christianity, propitiation is a theological term denoting that by which God is rendered propitious, i.e., that 'satisfaction' or 'appeasement' by which it becomes consistent with His character and government to pardon and bless sinners. ...
To atone or make reparation for; To make amends or pay the penalty for; To relieve or cleanse of guilt
(Expiation) The removal of the sin barrier, once dividing God from His elect, through the death of Jesus Christ.
(expiation) A process of removing or receiving forgiveness for sin; atonement. Although it is often confused with propitiation, another type of atonement, expiation specifically looks at the object causing the sin, not at God and the repair of a broken relationship with God. ...
(EXPIATION) The doctrine of expiation or atonement for neglected duties, sins of omission and commission, is distinguished in the Muslim religion from the doctrine of sacrifice; sacrifices being strictly confined to the 'Idu 'l-Azha', or Feast of Sacrifice in the month of pilgrimage.
(Expiation) Being a bad guy makes us dirty because of all the sin and bad we do. Jesus dying for us and us believing in him, washes that away and makes us clean.