72 The second end is duly to give thanks to God. Only the divine Redeemer, as the eternal Father's most beloved Son whose immense love He knew, could offer Him a worthy return of gratitude. This was His intention and desire at the Last Supper when He "gave thanks." He did not cease to do so when hanging upon the cross, nor does He fail to do so in the august sacrifice of the altar, which is an act of thanksgiving or a "eucharistic" act; since this "is truly meet and just, right and availing unto salvation."
Source: Mediator Dei (Vatican.va)