From the Catechism of the Catholic Church
CCC 1380 In his Eucharistic presence he remains mysteriously in our midst as the one who loved us and gave himself up for us and he remains under signs that express and communicate this love: The Church and the world have a great need for Eucharistic worship. Jesus awaits us in this sacrament of love. Let us not refuse the time to go to meet him in adoration, in contemplation full of faith, and open to making amends for the serious offenses and crimes of the world. Let our adoration never cease.
CCC 1377 The Eucharistic presence of Christ begins at the moment of the consecration and endures as long as the Eucharistic species subsist.