By St. Athanasius the Great
And once more, if the devil, the enemy of our race, having fallen from heaven, wanders about our lower atmosphere, and there bearing rule over his fellow spirits, as his peers in disobedience, not only works illusions by their means in them that are deceived, but tries to hinder them that are going up (and about this the Apostle says: "According to the prince of the power of the air, of the spirit that now works in the sons of disobedience" [Eph. 2:2]); while the Lord came to cast down the devil, and clear the air and prepare the way for us up into heaven, as said the Apostle: "Through the veil, that is to say, His flesh" [Heb. 10:20] — and this must needs be by death — well, by what other kind of death could this have come to pass, than by one which took place in the air, I mean the cross? For only he that meets his end on the cross dies in the air. Whence it was quite fitting that the Lord suffered this death. For thus being lifted up He cleared the air of the malignity both of the devil and of demons of all kinds, as He says: "I beheld Satan as lightning fall from heaven" [Lk. 10:18]; and made a new opening of the way up into heaven as He says once more: "Lift up your gates, O you princes, and be lifted up, you everlasting doors" [Ps. 24:9]. For it was not the Word Himself that needed an opening of the gates, being Lord of all; nor were any of His works closed to their Maker; but we it was that needed it, whom He carried up by His own body. For as He offered it to death on behalf of all, so by it He once more made ready the way up into the heavens.
From On the Incarnation.