Have you ever read
Memoriale Domini?
Here’s part of what the Sacred Congregation for Divine Worship said on May 19, 1969 about the early practice of receiving Communion in the hand:
It is certainly true that ancient usage once allowed the faithful to take this divine food in their hands and to place it in their mouths themselves.
It is also true that in very ancient times they were allowed to take the Blessed Sacrament with them from the place where the holy sacrifice was celebrated. This was principally so as to be able to give themselves Viaticum in case they had to face death for their faith.
However, the Church’s prescriptions and the evidence of the Fathers make it abundantly clear that the greatest reverence was shown the Blessed Sacrament, and that people acted with the greatest prudence. Thus, “let nobody . . . eat that flesh without first adoring it”(2) As a person takes (the Blessed Sacrament) he is warned: " . . . receive it: be careful lest you lose any of it."(3) “For it is the Body of Christ.”(4)
Further, the care and the ministry of the Body and Blood of Christ was specially committed to sacred ministers or to men specially designated for this purpose: “When the president has recited the prayers and all the people have uttered an acclamation, those whom we call deacons distribute to all those present the bread and wine for which thanks have been given, and they take them to those who are absent.”(5)
Soon the task of taking the Blessed Eucharist to those absent was confided to the sacred ministers alone, so as the better to ensure the respect due to the sacrament and to meet the needs of the faithful. Later, with a deepening understanding of the truth of the eucharistic mystery, of its power and of the presence of Christ in it, there came a greater feeling of reverence towards this sacrament and a deeper humility was felt to be demanded when receiving it. Thus the custom was established of the minister placing a particle of consecrated bread on the tongue of the communicant.
This method of distributing holy communion must be retained, taking the present situation of the Church in the entire world into account, not merely because it has many centuries of-tradition behind it, but especially because it expresses the faithful’s reverence for the Eucharist. The custom does not detract in any way from the personal dignity of those who approach this great sacrament: it is part of that preparation that is needed for the most fruitful reception of the Body of the Lord.(6)
This reverence shows that it is not a sharing in “ordinary bread and wine”(7) that is involved, but in the Body and Blood of the Lord, through which “The people of God share the benefits of the Paschal Sacrifice, renew the New Covenant which God has made with man once for all through the Blood of Christ, and in faith and hope foreshadow and anticipate the eschatological banquet in the kingdom of the Father.”(8)
Further, the practice which must be considered traditional ensures, more effectively, that holy communion is distributed with the proper respect, decorum and dignity. It removes the danger of profanation of the sacred species, in which “in a unique way, Christ, God and man, is present whole and entire, substantially and continually.”(9) Lastly, it ensures that diligent carefulness about the fragments of consecrated bread which the Church has always recommended: “What you have allowed to drop, think of it as though you had lost one of your own members.”(10)
When therefore a small number of episcopal conferences and some individual bishops asked that the practice of placing the consecrated hosts in the people’s hands be permitted in their territories, the Holy Father decided that all the bishops of the Latin Church should be asked if they thought it opportune to introduce this rite. A change in a matter of such moment, based on a most ancient and venerable tradition, does not merely affect discipline. It carries certain dangers with it which may arise from the new manner of administering holy communion: the danger of a loss of reverence for the august sacrament of the altar, of profanation, of adulterating the true doctrine.