Approaching the altar

The faithful [...] understood well that they all partook both in the offering of the Mass and in the receiving of the Eucharist, both in sacrifice-oblation and sacrifice-banquet. The ancient ceremonial brought this out very plainly. The faithful approached the altar at the Offertory and at the Communion, first to give and later to receive. The Mass was both their gift to God through Christ and God's gift to them through Christ.

Fr. Busch, Orate Fratres vol. II, no. 5

quoted in Fr. Martin Hellriegel's The Holy Sacrifice of the Mass, p. 41 (1944)