"Kneeling in adoration before the Lord" is "the most valuable and radical remedy against the idolatries of yesterday and today... Kneeling before the Eucharist is a profession of freedom: those who bow to Jesus cannot and must not prostrate themselves before any earthly authority, however powerful. We Christians kneel only before God or before the Most Blessed Sacrament because we know and believe that the one true God is present in it, the God who created the world and so loved it that he gave his Only Begotten Son (cf. Jn 3: 16). " (Benedict XVI, May 22, 2008)
Full text of the homily can be found at:
http://www.vatican.va/news_services/or/or_eng/text.html