Shrove Tuesday is the day on which traditionally we prepare for Lent by receiving the Sacrament of Penance or Reconciliation. For many the idea of confessing one's sins ("being shriven" in old parlance) is hard to understand; for many more it is hard to practise. It may be useful, therefore, to recapitulate what the Sacrament is and why it matters.

Only God can forgive sin. The priest acts in God's name, in accordance with the power and charge given him in the Sacrament of Order; and forgiveness is by no means automatic. The penitent must confess, make satisfaction, perform the penance imposed on him and have a firm purpose of amendment for the future. It is not enough just to rattle off a "laundry list", whip through an Act of Contrition, reel off an "Our Father" or two and assume all is well in this world and the next. Sin matters because it binds us and God wants his children to be free, but we have to do our part in responding to the invitation God makes in this Sacrament.

The first stumbling-block for some is the act of confession. To examine one's conscience in the light of the gospel can be painful in itself. Try reading 1 Corinthinans 13, putting your own name where St Paul puts the word "love" and you will soon see where you are wanting! Trying to articulate this murky side of oneself is certainly humbling, but it is also remarkably liberating. Sin's power over us is the power of darkness and concealment which confession breaks by allowing light and healing in. In a sense, the Sacrament is already work when we realise that we are sinners and have fallen short of God's glory.

Being sorry for one's sins is sometimes another difficulty. Here it is important to remember that it is not what one feels but what one intends that matters. If one is resolved to try one's hardest not to commit a particular sin again, there is no need to try to manufacture a feeling one doesn't honestly feel.

Making satisfaction for one's sins is often overlooked but is absolutely essential. If, for example, one has harmed someone by speaking ill of them, one must do all one can to put matters right. That may require a public humility which makes one squirm. Tough. Sin is serious; so is grace. Or there may be sin that no one but oneself knows about, but that too must be put right if one can. Confessing one's sins to a priest not only reveals them for what they are, it also makes one aware how clever we can be in finding excuses for them or minimizing their importance: having to do something about them strips this false comfort from us.

The penance imposed by the priest refers to the temporal punishment due to sin. By confessing we acknowledge we have injured the whole Body of Christ and we are required to make amends, hence the penance. It must be performed diligently and as soon as possible. Finally, there is that firm purpose of amendment for the future and our gratitude to God for what he has done for us.

Conversion, confession, celebration: this is the threefold pattern of the Sacrament of Penance which prepares us for Lent. It is not all doom and gloom. But before we clear our larders of eggs and fats for the Lenten fast, before we set our first pancake sizzling in the pan, let us remember what Lent is about. It is our great Festival of Freedom as Christians, and a necessary part of our preparation is the acknowledgement of our entanglement in sin.

This week's podcast (to be posted tomorrow) will be longer than usual and will be part of the prioress's Chapter talk for Ash Wednesday.