by Dominic V. Cassella.

As a Byzantine Catholic, I can always tell if someone has little exposure to the Eastern Christian tradition because of two things. One, when they visit a Byzantine Church, they will genuflect when entering the pew - while many Eastern Catholics will make a bow with the sign of the cross. And two, they will kneel during the consecration and after receiving the Eucharist.

Now, while I never thought twice about kneeling in a Roman Church or genuflecting before sliding into the pew, watching Roman Catholics kneel at a Byzantine Church used to irk me: "I kneel at your Church, why don't you stand at mine?"

And while I recognize kneeling as an act of piety, I think it is worth explaining precisely why Byzantine Catholics do not kneel on Sunday, in case anyone reading this may find themselves there. (I'll leave Cardinal Cupich's controversial order that Chicago Catholics should not kneel at altar rails to receive Communion - based on notions of traffic flow - which is quite a different subject for another day.)

To do this, we have to go back 1700 years to the Council of Nicaea - the anniversary of which we celebrate this year. At the Council, the Fathers of the Church mainly deliberated and debated Christology, resulting in the condemnation of Arianism. However, they also laid out various canons concerning liturgical practice and calendrical systems.

Many people today might not know that at the Council of Nicaea, the Church declared in Canon 20 that there should be no kneeling on the Lord's Day or during the Pentecost season.

Several questions arise when we consider this Canon: Why on earth would the First Holy Ecumenical Council of the Church think it important to forbid kneeling on Sundays and during the season of Pentecost? Did not Benedict XVI in The Spirit of the Liturgy remind us of the story of an old Abbot who saw the Devil, black and ugly as he was, with no knees? Isn't the inability to kneel the very essence of the diabolical? (Philippians 2:10)

In On the Holy Spirit (27.66), Basil the Great explains this practice and gives the reason, which explains why, to this day, Eastern Catholics do not kneel on Sunday.

Writing just a few decades after the Council of Nicaea, Basil tells us that:

We all stand for prayer on Sunday, but not everyone knows why. We stand for prayer on the day of the Resurrection to remind ourselves of the graces we have been given: not only because we have been raised with Christ and are obliged to seek the things that are above, but also because Sunday seems to be an image of the age to come. . . .It is, therefore, necessary for the Church to teach her newborn children to stand for prayer on this day [Sunday], so that they will always be reminded of eternal life, and not neglect preparations for their journey.

Basil tells us that the early Church (and still the Eastern Christians today) stood on Sundays when they prayed so that they were not neglectful of the journey. In saying this, we learn that standing on Sunday echoes God's command to the Israelites in Egypt, who were told to eat the Passover with "your loins girded, your sandals on your feet, and your staff in your hand; and you shall eat it in haste. It is the LORD's Passover." (Exodus 12:11)

The passion, death, and resurrection of Jesus Christ is the new Passover. He is the Lamb of God. (John 1:29) When they partook of the Eucharistic celebration of this new Passover on Sunday, like the Israelites in Egypt, the early Christians remained standing because they understood themselves as the pilgrim Church.

The word pilgrim comes from the Latin per, which means "beyond," and agri, which means "country or land;" literally, a pilgrim is someone who is "beyond or outside of their country." When we are baptized into Christ and put on Christ, our Kingdom and homeland is not of this world. (John 18:36) Instead, by becoming Christians, we are made citizens of a new nation, the City of God. As citizens of God's Kingdom, we are essent...