From the early Church Fathers to now.
“And their faces, and their wings were stretched upward: two wings of every one were joined, and two covered their bodies:”
“Two are stretched out and lift themselves up on high and signify heavenly preaching, in everything that pertains to the majesty of God. Two cover their bodies, for human knowledge is excluded, and perfect consideration is not offered.”
“(Verse 11) And their faces and wings were stretched out from above, with two wings of each joined together and two covering their bodies. And above we have said that the Gospels and the seasons are joined together, and all rational creatures, and the four virtues, so that whoever lacks one lacks all. And that the two are stretched out and rise up high signifies heavenly preaching and all things tending towards the majesty of God. But two things hinder the knowledge of bodies: human knowledge is excluded, and perfect intuition is not provided, as the Apostle says: For we know in part, and we prophesy in part. But when that which is perfect has come, then that which is in part will be done away with (1 Cor. 13:9).”
“He shows by these things not that everything is to be understood by divine power but that some things are clear to them and others are unknown, and they do not go beyond the limit set down for them. They stretch out two wings in their exultation, for the gift of contemplation has been granted, and they cover their bodies with two wings, covering those things that are hidden in happy ignorance, and they do not struggle in order to observe things that it is not right for them to see.”
“The face and the extended wings are described above because every intention and every contemplation of the saints stretches beyond itself, so that it may attain what it desires in heavenly things. For whether one is vigilant in good work or in contemplation, then what one does is truly good when one desires to please Him from whom it comes. For he who appears to do good things but through these desires to please not God but men presses down the face of his intention. And he who contemplates in sacred Scripture the things that pertain to divinity so that through what he understands he might be occupied with disputes—because he does not desire to be satisfied by the sweetness of the sought-after blessedness but rather to appear learned—such a one certainly does not extend the wings of his understanding upward; but because he occupies the vigilance of his mind in earthly desire, he lays down in the depths the wings which he could have raised on high and by which he himself could have been raised. In this matter it must be considered that every good that is done should always be raised toward heavenly things through intention. For he who through the good things he does desires earthly glory presses down his wings and his face. Hence through the prophet it is said of certain ones: "They were carrying their victims down into the depths." For what else are the tears of prayer but the victims of our offering? As it is written: "A sacrifice to God is a troubled spirit." And there are some who afflict themselves with lamentations in prayer in order to acquire earthly benefits or to appear holy to men. What do these do but carry their victims into the depths? Because the things they seek are in the lowest place, they lay down the sacrifice of their prayer below. But the elect, who desire to please almighty God in good work and through the grace of contemplation long to taste eternal blessedness even now, extend their faces and wings above.”
“It had been said: "And their faces and their wings were stretched out above," and immediately what we have brought forward was added, that "two wings of each were joined." Here it is openly understood that they were both stretched out above and joined, while two covered their bodies. But what are the wings of the animals called except pinions? In this matter we must inquire with diligent investigation what the four wings of the saints are, of which two stretched out above are joined, while two cover their bodies. For if we look attentively, we find there are four virtues that lift every winged creature from earthly actions: namely, love and hope concerning future things, but fear and penitence concerning past things. Therefore the wings joined to each other are stretched out above, because love and hope lift the mind of the saints to things above. These are also fittingly called joined, because the elect without doubt both love the heavenly things they hope for and hope for what they love. But two cover their bodies, because fear and penitence hide their past evils from the eyes of almighty God. Thus two wings, as was said, are joined above, when love and hope elevate the hearts of the elect to higher things, suspend them toward heavenly things. But two wings cover their bodies, when fear and penitence hide their past evils from the sight of the eternal judge. For in that they remember that they have sinned, because they fear greatly and weep, what else do they do but cover their body? They who hide their carnal deeds from the strict examination by good works placed over them. For it is written: "Blessed are they whose iniquities are forgiven, and whose sins are covered." For we cover sins when we place good deeds over evil actions. For everything that is covered is placed beneath; and that by which it is covered is drawn over it from above. Therefore when we renounce the evils we have done and choose the good things we should do, we as it were draw a covering over that thing which we are ashamed to have seen.”
“However holy men may be in this life, they still have that which they ought to cover before the eyes of God, because it is utterly impossible that they should never sin in deed, or in speech, or in thought. Hence blessed Job, who had indeed spoken perfect things to men, yet hearing the voice of God and reproving himself for that very perfect speech of his, said: "I will lay my hand upon my mouth." For in the hand is work, in the mouth is speech. Therefore to lay the hand upon the mouth is to cover the sins of speech by the virtue of good work. It pleases me, dearest brothers, to call the teacher of the Gentiles as a witness to this matter, and to see how that holy living creature rests upon four wings, of which with two it flies upward; but with two wings it covers its body, because it hides the past things it had done. Let us see, therefore, how great a love raises him to heavenly things: "For me to live is Christ, and to die is gain." Let us recognize with how great a hope he is raised to higher things: "Our citizenship is in heaven, from whence also we look for the Savior Jesus Christ our Lord." Let us see if, even when established in such great virtues, he still fears: "I chastise my body and bring it into subjection, lest perhaps, when I have preached to others, I myself should become a castaway." Let us recognize if he repents of having done evil: "I am the least of the apostles, who am not worthy to be called an apostle, because I persecuted the Church of God." In these words of his, what else is accused but the hardness of our mind? Because he mourns what he had committed before baptism, while we have committed many things even after baptism, and yet we refuse to weep. Therefore the holy living creatures use four wings, because through love and hope they fly to heavenly things, and through fear and repentance they lament the unlawful deeds within themselves.”
“But because it was said: "The two wings of each were joined," this is perhaps understood to mean that they do not join their own wings by raising them, but that the wings of one are conjoined to another, so that evidently the raised wings mutually agree with each other in their joining. In this matter a question arises: if the two wings that elevate designate love and hope, while the two that cover the bodies designate fear and penitence, why are the two that are extended said to be conjoined, and the two that cover the body are not said to be? But in this matter, by the Lord's granting, an easy explanation presents itself: the two wings of the saints that are conjoined are love and hope, while the two that cover the bodies are not conjoined to one another, namely fear and penitence. For David was afflicted by fearing and doing penance for the fall of the flesh. Peter wept bitterly for the fall of faithlessness. Paul laments the cruelty of his past persecution in himself. Yet all seek one homeland, all hasten to reach the one author of all things. Therefore the two wings of each are conjoined, and the two are not, because through love and hope what they desire is one, but through fear and penitence what they lament is diverse.”
The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.