Holy Communion from the Tabernacle
Concern is often raised about the continuing practice of communicating the assembly at Mass from the sacrament reserved in the tabernacle. The Constitution on the Liturgy, art. 55, states: "The more complete form of participation in the Mass by which the faithful, after the priest's communion, receive the Lord's body from the same sacrifice, is strongly endorsed" (emphasis added). This is supported in the General Instruction of the Roman Missal, no. 85, which states that "it is most desirable that the faithful, just as the priest himself is bound to do, receive the Lord's body from hosts consecrated at the same Mass and that, in the instances when it is permitted, they partake of the chalice.(cf. no. 283), so that even by means of the signs Communion will stand out more clearly as a participation in the sacrifice actually being celebrated."
The reason for which the Church reserves the eucharist outside Mass is, primarily, the administration of viaticum to the dying and, secondarily, communion of the sick, communion outside Mass, and adoration of Christ present in the sacrament (see Holy Communion and Worship of the Eucharist outside Mass, no. 5). Only under rare circumstances of necessity should the assembly at Mass communicate from the reserved sacrament in the tabernacle.