This, rather, is the fasting that I wish: releasing those bound unjustly, untying the thongs of the yoke; Setting free the oppressed breaking every yoke; Sharing your bread with the hungry, sheltering the oppressed and the homeless; Clothing the naked when you see them, and not turning your back on your own. (Is 58:1-9a)
https://bible.usccb.org/bible/readings/030422.cfm
According to Pope Francis, God’s weapons are prayer and fasting—but fasting is always about doing justice. We pray for peace and justice for Ukraine.