Abide in me, and I in you
"When the disciples on the way to Emmaus asked Jesus to stay 'with' them, he responded by giving them a much greater gift: through the Sacrament of the Eucharist he found a way to stay 'in' them. Receiving the Eucharist means entering into a profound communion with Jesus. 'Abide in me, and I in you' (John 15:4). This relationship of profound and mutual 'abiding' enables us to have a certain foretaste of heaven on earth. Is this not the greatest of human yearnings? Is this not what God had in mind when he brought about in history his plan of salvation? God has placed in human hearts a 'hunger' for his word (cf. Amos 8:11), a hunger which will be satisfied only by full union with him. Eucharistic communion was given so that we might be 'sated' with God here on earth, in expectation of our complete fulfilment in heaven."
John Paul II, Apostolic Letter Mane Nobiscum Domine, 19