The day of fasting, prayer, and repentance.

This Friday, October 27, Pope Francis declared a day of fasting, prayer, and penance. The Holy Father asks all local churches to join together in praying for peace for the whole world.
His call was made during the general audience on Wednesday, October 18:

Brothers and sisters, let us continue to pray for peace, and let us not forget the battered Ukraine, which is not being spoken of now, but whose tragedy continues.

Today, our thoughts also turn to Palestine and Israel. The number of victims is rising, and the situation in Gaza is desperate. I ask that everything possible be done to prevent a humanitarian disaster.

It is very alarming that the conflict could widen, as there are already so many open war fronts in the world! May the weapons fall silent! Let us be attentive to the desperate cries of the population, of people, children, calling for peace! Brothers and sisters, war does not solve any problem: it only sows death and destruction, fuels hatred, and feeds the desire for revenge. War erases the future. I urge all believers: let us take a stand on one side of the conflict, the side of peace. But not with words – with prayer and total surrender.

With this in mind, I have decided to ask that Friday, October 27, be a day of fasting, prayer, and penance. I invite brothers and sisters of all Christian denominations, I invite all believers regardless of religion, I invite all people who care about peace in the world to participate as they see fit.

On Friday at six o'clock in the evening, we will unite for an hour at St. Peter's in a penitential prayer, during which we will urgently ask for peace for our time, for this world. I ask all local churches to organize similar gatherings and involve God's people in them.

Source: https://www.vatican.va/content/francesco/en/audiences/2023/documents/20231018-udienza-generale.html