Let us lift up our hearts.
We lift them up unto the Lord.
(From the Divine Liturgy)
St. Cyril of Jerusalem writing in the 4th Century describes a portion of the Divine Liturgy which is basically the same as we Orthodox are still doing today.
After the priest cries out, “Lift up your hearts.”
For truly that awe-filled hour it is necessary to have our hearts up toward the Lord, and not below with regard to the earth and earthly activities. For this reason the priest exhorts you with authority in that hour to leave behind all everyday cares and household worries and to have your hearts in heaven with the God who is the lover of humanity. Next, you answer, “We have lifted them to the Lord,” having made by this your agreement with him according to what you confessed. But let not such a one enter who with the mouth says, “We have lifted them up to the Lord,” but whose thoughts in the mind are focused on everyday cares. Always, then, keep God in mind! But if, on account of human weakness, you are not able to do this, try to do it especially in that hour. (Lectures on the Christian Sacraments, p. 123)
Let us who mystically represent the Cherubim … now lay aside all earthly cares as we receive the King of All who comes invisibly upborne by the angelic hosts. (Cherubimic Hymn of the Divine Liturgy)