From the Prologue from Ochrid:
… in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience (Ephesians 2:2).
This is all one and the same path-the path to destruction. According to the course of this world means inclination toward sinfulness; according to the prince of the power of the air means according to the will of those chiefs of the demons who inhabit the air; in the spirit that now worketh in the children of disobedience means that in the same way that the opponents and adversaries of God now live, all men lived before the advent of Christ, including those to whom the Apostle writes the epistle.
What is this power of the air, brethren? This is the order of evil spirits who exist in constant movement in the air. They make the air lethal and they impede the souls of the departed as they make their way to heaven. They deceive the spirit of man to work every evil; they tempt it with every sin. Yet, they do not command the spirit to sin, for they lack the power to do that; they can only tempt and corrupt. They acted more strongly and directly on the pagans than on the Israelites. They fell upon the pagans as a swarm of flies on a carcass, but the Israelites they watched from a distance, corrupting and tempting them more subtlely. They stood at a distance from Israel because of the name of God, which was preserved and spoken among the Israelites.
The Lord Jesus Christ scattered them all and plucked out their poisonous stings, so that they remained only as empty phantoms, as miserable, inconstant shadows that vanish instantly at the mention of the name of Christ or at the tracing of the sign of Christ's Cross.
O Lord Jesus, our Commander and Deliverer, help us to live in Thy freedom.
To Thee be glory and praise forever. Amen.