"The individual Bishops are the Visible Source and Foundation of Unity in their own particular Churches." 408 As such, they "Exercise their pastoral Office over the portion of the People of God assigned to them," 409 assisted by Priests and deacons. But, as a member of the episcopal college, each Bishop Shares in the concern for all the Churches. 410 The bishops exercise this Care first "by ruling well their own Churches as portions of the Universal Church," and so contributing "to the welFare of the whole Mystical Body, which, from another point of view, is a corporate body of Churches." 411 They extend it Especially to the Poor, 412 to those persecuted for the Faith, as well as to Missionaries who are working Throughout the world.