From 96 year old Monsignor Foy…
“I was recently contacted with concerns that some clergy and laity need to be reminded that they should genuflect when they pass by the Tabernacle. In response, I am posting the following sources in support of the reception of Holy Communion on the tongue, kneeling, genuflecting, the restoration of Communion rails, centrally-placed Tabernacles and having the priest celebrant face the Tabernacle and worship God with the people at Mass. These have been longtime traditions of the Roman Rite of the Catholic Church.
Kneeling “officially signifies adoration” (Ceremonial of Bishops, Nos. 68-72 p.36-37).
“One waits for symbols and promises standing, but the Reality, one receives with love and on one’s knees” (Pope Saint Pius X).
“The Catholic Church has always offered and still offers the worship of latria [adoration] to the Sacrament of Eucharist” (Pope Paul VI, Mysterium Fidei, 1965, n.56).
“No one eats of this flesh without having first adored it and not only do we not sin by adoring but we would sin by not adoring” (Ibid., n.55, St. Augustine, In Ts, Ch.98, 9:PL 37, 126).”
Read on… Venite Adoremus! O Come Let us Adore Him!
Why Catholics genuflect before the tabernacle
Eucharistic adoration and genuflection express belief in the Real Presence of Jesus Christ. When the Blessed Sacrament is reserved in the tabernacle, a genuflection is a bodily act of worship directed to Christ, not merely a gesture toward a church furnishing. Done attentively, this simple practice helps unite outward reverence with interior faith and reminds Catholics that the Lord they receive at Mass remains truly present.