A day of darkness, etc - The depredations of the locusts are described from the second to the eleventh verse, and their destruction in the twentieth. Dr. Shaw, who saw locusts in Barbary in 1724 and 1725, thus describes them: -

"I never observed the mantes, bald locusts, to be gregarious. But the locusts, properly so called, which are so frequently mentioned by sacred as well as profane writers, are sometimes so beyond expression. Those which I saw in 1724 and 1725 were much bigger than our common grasshopper; and had brown spotted wings, with legs and bodies of a bright yellow. Their first appearance was toward the latter end of March, the wind having been for some time south. In the middle of April their numbers were so vastly increased that, in the heat of the day, they formed themselves into large and numerous swarms; flew in the air like a succession of clouds; and, as the prophet Joel expresses it, (Joel 2:10) they darkened the sun. When the wind blew briskly, so that these swarms were crowded by others, or thrown one upon another, we had a lively idea of that comparison of the psalmist, (Psalm 109:23), of being 'tossed up and down as the locust.' In the month of May, when the ovaries of those insects were ripe and turgid, each of these swarms began gradually to disappear; and retired into the Mettijiah, and other adjacent plains, where they deposited their eggs. These were no sooner hatched in June, than each of these broods collected itself into a compact body of a furlong or more in square; and, marching immediately forward in the direction of the sea, they let nothing escape them; eating up every thing that was green and juicy, not only the lesser kinds of vegetables, but the vine likewise; the fig tree, the pomegranate, the palm, and the apple tree, even all the trees of the field, Joel 1:12; in doing which they kept their ranks like men of war; climbing over, as they advanced, every tree or wall that was in their way. Nay, they entered into our very houses and bedchambers, like so many thieves. The inhabitants, to stop their progress, made a variety of pits and trenches all over their fields and gardens, which they filled with water; or else they heaped up in them heath, stubble, and such like combustible matter, which were severally set on fire upon the approach of the locusts. But this was all to no purpose, for the trenches were quickly filled up, and the fires extinguished, by infinite swarms succeeding one another; while the front was regardless of danger, and the rear pressed on so close, that a retreat was altogether impossible. A day or two after one of these broods was in motion, others were already hatched to march and glean after them; gnawing off the very bark, and the young branches, of such trees as had before escaped with the loss only of their fruit and foliage. So justly have they been compared by the prophet Joel (Joel 2:3) to a great army; who further observes, that 'the land is as the garden of Eden before them and behind them a desolate wilderness.'

"Having lived near a month in this manner (like a μυριοστομον ξιφος, or sword with ten thousand edges, to which they have been compared), upon the ruin and destruction of every vegetable substance which came in their way, they arrived at their full growth, and threw old their nympha state by casting their outward skin. To prepare themselves for this change, they clung by their hinder feet to some bush, twig, or corner of a stone; and immediately, by using an undulating motion, their heads would first break out, and then the rest of their bodies. The whole transformation was performed in seven or eight minutes, after which they lay for a short time in a torpid and seemingly languishing condition; but as soon ad the sun and air had hardened their wings, by drying up the moisture which remained upon them, after casting their sloughs, they reassumed their former voracity, with an addition both of strength and agility. Yet they did not continue long in this state before they were entirely dispersed, as their parents were before, after they had laid their eggs; and as the direction of the marches and flights of them both was always to the northward, and not having strength, as they have sometimes had, to reach the opposite shores of Italy France, or Spain, it is probable they perished in the sea, a grave which, according to these people, they have in common with other winged creatures." - Travels, 4to. edition pp. 187, 188.

A day of darkness - They sometimes obscure the sun. And Thuanus observes of an immense crowd, that "they darkened the sun at mid-day."

As the morning spread upon the mountains - They appeared suddenly: as the sun, in rising behind the mountains, shoots his rays over them. Adanson, in his voyage to Senegal, says: "Suddenly there came over our heads a thick cloud which darkened the air, and deprived us or the rays of the sun. We soon found that it was owing to a cloud of locusts." Some clouds of them are said to have darkened the sun for a mile, and others for the space of twelve miles! See the note on Joel 2:10 (note).

A day of darkness. The quantity of these insects, says a French author,is incredible to all who have not themselves witnessed their astonishing numbers; the whole earth is covered with them for the space of several leagues. The noise they make in browsing on the trees and herbage may be heard at a great distance, and resembles that of an army in secret. Wherever their myriads spread, the verdure of the country disappears; trees and plants, stripped of their leaves and reduced to their naked boughs and stems, cause the dreary image of winter to succeed in an instant to the rich scenery of spring. When these clouds of locusts take their flight, to surmount any obstacles or to traverse more rapidly a desert soil, the heavens may literally be said to be obscured by them.

Joel 2:10,31 The earth shall quake before them; the heavens shall tremble: the sun and the moon shall be dark...

Joel 3:14,15 Multitudes, multitudes in the valley of decision: for the day of the LORD is near in the valley of decision...

Exodus 20:21 And the people stood afar off, and Moses drew near to the thick darkness where God was.

Psalm 97:2 Clouds and darkness are round about him: righteousness and judgment are the habitation of his throne.

Isaiah 5:30 And in that day they shall roar against them like the roaring of the sea: and if one look to the land, behold darkness and sorrow...

Isaiah 8:22 And they shall look to the earth; and behold trouble and darkness, dimness of anguish; and they shall be driven to darkness.

Jeremiah 13:16 Give glory to the LORD your God, before he cause darkness, and before your feet stumble on the dark mountains, and...

Amos 5:18-20 Woe to you that desire the day of the LORD! to what end is it for you? the day of the LORD is darkness, and not light...

Zephaniah 1:14,15 The great day of the LORD is near, it is near, and hastens greatly, even the voice of the day of the LORD...

Hebrews 12:18 For you are not come to the mount that might be touched, and that burned with fire, nor to blackness, and darkness, and tempest,

Jude 1:13 Raging waves of the sea, foaming out their own shame; wandering stars, to whom is reserved the blackness of darkness for ever.

as.

Amos 4:13 For, see, he that forms the mountains, and creates the wind, and declares to man what is his thought, that makes the morning darkness...

a great.

Joel 2:5,11,25 Like the noise of chariots on the tops of mountains shall they leap, like the noise of a flame of fire that devours the stubble...

Joel 1:6 For a nation is come up on my land, strong, and without number, whose teeth are the teeth of a lion...

there.

Joel 1:2,3 Hear this, you old men, and give ear, all you inhabitants of the land. Has this been in your days...

Exodus 10:6,14 And they shall fill your houses, and the houses of all your servants, and the houses of all the Egyptians; which neither your fathers...

Daniel 12:1 And at that time shall Michael stand up, the great prince which stands for the children of your people...

Mark 13:19 For in those days shall be affliction, such as was not from the beginning of the creation which God created to this time...

many generations. Heb. generation and generation.

Deuteronomy 32:7 Remember the days of old, consider the years of many generations: ask your father, and he will show you; your elders...

Psalm 10:6 He has said in his heart, I shall not be moved: for I shall never be in adversity.

Distinction Between Exterior and Interior Actions --Those of the Soul in this Condition are Interior, but Habitual, Continued, Direct, Profound, Simple, and Imperceptible --Being a Continual
The actions of men are either exterior or interior. The exterior are those which appear outwardly, and have a sensible object, possessing neither good nor evil qualities, excepting as they receive them from the interior principle in which they originate. It is not of these that I intend to speak, but only of interior actions, which are those actions of the soul by which it applies itself inwardly to some object, or turns away from some other. When, being applied to God, I desire to commit an …
Jeanne Marie Bouvières—A Short Method Of Prayer And Spiritual Torrents

Whether all are Bound to Keep the Fasts of the Church?
Objection 1: It would seem that all are bound to keep the fasts of the Church. For the commandments of the Church are binding even as the commandments of God, according to Lk. 10:16, "He that heareth you heareth Me." Now all are bound to keep the commandments of God. Therefore in like manner all are bound to keep the fasts appointed by the Church. Objection 2: Further, children especially are seemingly not exempt from fasting, on account of their age: for it is written (Joel 2:15): "Sanctify a fast," …
Saint Thomas Aquinas—Summa Theologica

Whether Christ had any Acquired Knowledge?
Objection 1: It would seem that in Christ there was no empiric and acquired knowledge. For whatever befitted Christ, He had most perfectly. Now Christ did not possess acquired knowledge most perfectly, since He did not devote Himself to the study of letters, by which knowledge is acquired in its perfection; for it is said (Jn. 7:15): "The Jews wondered, saying: How doth this Man know letters, having never learned?" Therefore it seems that in Christ there was no acquired knowledge. Objection 2: Further, …
Saint Thomas Aquinas—Summa Theologica