Father Hunwicke has posted this very helpful quotation from the great Anglican Benedictine and mystagogue Dom Gregory Dix. It explains why every Christian is obliged to be at Mass every Sunday:
"To secure [the Sunday Corporate Eucharist] a whole congregation of obscure provincials at Abilinitina in Africa took the risk of almost certain detection by assembling at the height of the Diocletian persecution in their own town, where the authorities were on the watch for them, because, as they said in court, the eucharist had been lacking a long while through the apostasy of their bishop Fundanus, and they could no longer bear the lack of it. And so they called on a presbyter to celebrate - and paid the penalty of their faith to a man. ...
"The christian came to the eucharist, not indeed 'to learn something', for faith was presupposed, but certainly not to seek a psychological thrill. He came simply to do something, which he conceived he had an overwhelming personal duty to do, come what may.
"What brought him to the eucharist week by week, despite all dangers and inconveniences, was no thrill provoked by the service itself, which was bare and unimpressive to the point of dullness, and would soon lose any attraction of novelty. Nor yet was it a longing for personal communion with God, which he could and did fulfil otherwise in his his daily communion from the reserved sacrament at home. What brought him was an intense belief that in the eucharistic action of the Body of Christ, as in no other way, he himself took part in that act of sacrificial obedience to the will of God which was consummated on Calvary and which had redeemed the world, including himself. What brought him was the conviction that there rested on each of the redeemed an absolute necessity to take his own part in the self-offering of Christ, a necessity more binding even than the instinct of self-preservation.
"Simply as members of Christ's body, the church, all christians must do this, and they can do it in no other way than that which was the last command of Jesus to his own. That rule of the absolute obligation upon each of the faithful of presence at Sunday mass under pain of mortal sin,which seems so mechanical and formal to the protestant, is something which was burned into the corporate mind of historic christendom in the centuries between Nero and Diocletian, but it rests upon something more evangelical and more profound than historical memories. It expresses as nothing else can the whole new testament doctrine of redemption; of Jesus, God and Man, as the only saviour of mankind, who intends to draw all men to him by his sacrificial and atoning death; and of the church as the communion of redeemed sinnners, the body of Christ, corporately invested with his own mission of salvation to the world."