The answer
It is common for people to remove their shoes upon entering churches in Coptic Orthodox monasteries. Most churches in other vicinities do not require that peopleremove their shoes before entering, but many will remove their shoes in the place where they are standing inside the church and definitely before partaking of the Holy
Eucharist. The reason for this tradition is a sign of reverence and respect in the presence of God.
“Then He said, ‘Do not draw near this place. Take your sandals off your feet, for the place where you stand is holy ground’” (Exodus 3:5).
"Then the Lord said to him, ‘Take your sandals off your feet, for the place where you stand is holy ground’” (Acts 7:33).
Answered by His Eminence Metropolitan Youssef (opens in a new tab)