Responsorial Psalm (Psalm 95)
R. If today you hear his voice, harden not your hearts. Come, let us sing joyfully to the LORD; let us acclaim the Rock of our salvation. Let us come into his presence with thanksgiving; let us joyfully sing psalms to him. R. If today you hear his voice, harden not your hearts.
https://bible.usccb.org/bible/readings/032422.cfm
The invitatory psalm, usually Psalm 95 (94), is the psalm that begins the first office of prayer in the Liturgy of the Hours. It “invites” to sing joyfully, to come into God's presence, to hear God’s voice, and to not harden our hearts. The response: “If today you hear his voice, harden not your hearts” is frequently heard during Lent. Today we continue our prayer for the Ukrainian people.