To this end, dialogue has its own contribution to make. More than an exchange of thoughts, an academic exercise, it is an exchange of gifts (cf. Ut Unum Sint, n. 28), in which the Churches and the Ecclesial Communities can make available their own riches (cf. Lumen Gentium, nn. 8, 15; Unitatis Redintegratio, nn. 3, 14ff.; Ut Unum Sint, nn. 10-14).