Catechism of the Catholic Church

Being seated at the Father's right hand signifies the inauguration of the Messiah's kingdom, the fulfillment of the prophet Daniel's vision concerning the Son of man: "To him was given dominion and glory and kingdom, that all peoples, nations, and languages should serve him; his dominion is an everlasting dominion, which shall not pass away, and his kingdom one that shall not be destroyed." After this event the apostles became witnesses of the "kingdom [that] will have no end." (541)