Pope Paul VI
“On the very day of Pentecost, when the Church appeared before the world, ‘those who received the word” of Peter “were baptized.’ And ‘they continued steadfastly in the teaching of the apostles and in the communion of the breaking of bread and in prayers . . . praising God and being in favor with all the people’ (Acts 2:41-47). From that time onwards the Church has never failed to come together to celebrate the paschal mystery: reading those things ‘which were in all the scriptures concerning him’ (Luke 24:27), celebrating the eucharist in which ‘the victory and triumph of his death are again made present’, and at the same time giving thanks ‘to God for his unspeakable gift’ (2 Cor. 9:15) in Christ Jesus, ‘in praise of his glory’ (Eph. 1:12), through the power of the Holy Spirit.”
Source: Pope Paul VI, SACROSANCTUM CONCILIUM, Constitution on the Sacred Liturgy, DECEMBER 4, 1963