7 What are “the shoes”? The shoes which we use, are the skins of dead beasts, the coverings of our feet. By this then are we bidden to renounce dead works. This Moses was admonished of in a figure, when the Lord speaking to him said, “Loose your shoes from off your feet; for the place wherein you stand is holy ground.” What ground is so holy as the Church of God? In it therefore let us stand, let us loose our shoes, let us, that is, renounce dead works. For as touching these shoes, wherewith we walk, the same my Lord again assures me. For if He had not been shod Himself, John would not have said of Him, “I am not worthy to unloose the latchet of His shoes.” Be there obedience then, let not a haughty severity steal over us. “I,” says one, “fulfil the Gospel, because I walk with naked feet.” Well, you can do it, I cannot. But let us both keep that which we both receive together. How? Let us glow with charity, let us love one another; and so it shall be, that I will love your strength, and you shall bear my weakness.
Source: Sermons on Selected Lessons of the New Testament (New Advent)