The Eucharistic Prayer begins with the preface, where we give thanks to God for everything he has done for his people, and in response sing the song of the angels at the throne of God along with the song of the people welcoming Jesus into Jerusalem.
In the Eucharist, we are called to lift up our hearts to the Lord, that is, to focus on God, in giving thanks, and not to be distracted by the cares of earth.