If the Church tells us that the Eucharist is an essential part of Sunday, this is no mere positivism or thirst for power. On Easter morning, first the women and then the disciples had the grace of seeing the Lord. From that moment on, they knew that the first day of the week, Sunday, would be his day, the day of Christ the Lord. The day when creation began became the day when creation was renewed. Creation and redemption belong together. That is why Sunday is so important.