Holy Trinity Sunday: God calls us to form one family with him; Glory be to the Father, the Son and the Holy Spirit, God who is now, who was then and who is to come. The Church wants to emphasise the mystery of the Holy Trinity in this celebration. St Athanasius said: If God can be understood by human intelligence, then God is not true; St Tertullian says: the Trinity comes from the two words "Tri" and "Unity" which mean three but one. The Church needs people to teach catechism to Christians; it needs witnesses to develop the faith. As Christians, we are supposed to be like God the Father, the Son and the Holy Spirit: to complement each other, to love each other...