CCC 788
© Libreria Editrice Vaticana Source: vatican.va
When his visible presence was taken from them, Jesus did not leave his disciples orphans. He promised to remain with them until the end of time; he sent them his Spirit. Cf. Jn 14:18; 20:22; Mt 28:20; Acts 2:33. As a result communion with Jesus has become, in a way, more intense: "By communicating his Spirit, Christ mystically constitutes as his body those brothers of his who are called together from every nation." LG 7.
Read the full chapter 3. I Believe in the Holy Spirit ¶683–1065