[The Prophet] gives the name of wings to the rays of the sun; and this comparison has much beauty, for it is taken from nature and most fitly applied to Christ. There is nothing, we know, more cheering and healing than the rays of the sun; for ill-savour would soon overwhelm us, even within a day, were not the sun to purge the earth from its dregs; and without the sun there would be no respiration. We also feel a sort of relief at the rising of the sun, for the night is a kind of burden. When the sun sets, we feel as it were a heaviness in all our members; and the sick are exhilarated in the morning and experience a change from the influence of the sun; for it brings to us healing in its wing. But the Prophet has expressed what is still more–that a clear sun in a serene sky brings healing; for there is an implied opposition between a cloudy or stormy time and a clear and bright season. During time of serenity we are far more cheerful, whether we be in health or in sickness; and there is no one who does not derive some cheerfulness from the serenity of the heavens: but when it is cloudy, even the most healthy feels some inconvenience.
According to this view Malachi now says that there would be healing in the wings of Christ, inasmuch as many evils were to be borne by the true servants of God; for if we consider the history of those times, it will appear that the condition of that people was most grievous. He now promises a change to them; for the restoration of the Church would bring them joy. See then in what way he meant there would be healing in the wings of Christ; for the darkness would be dissipated, and the heavens would be free from clouds, so as to exhilarate the minds of the godly.
By calling the godly those who fear God, he adopts the common language of Scripture; for we have said that the chief part of righteousness and holiness consists in the true worship of God: but something new is here expressed; for this fear is what peculiarly belongs to true religion, so that men submit to God though he is invisible, though he does not address them face to face, though he does not openly show his hand armed with scourges. When therefore men of their own accord reverence the glory of God, and acknowledge that the world is governed by him, and that they are under his authority, this is a real evidence of true religion: and this is what the Prophet means by name. Hence they who fear the name of God desire not to draw him down from heaven, nor seek manifest signs of his presence, but suffer their faith to be thus tried so that they adore and worship God though they see him not face to face, but only through a mirror and that darkly, and also through the displays of his power, justice, and other attributes, which are evident before our eyes.