(Verse 18) - And on my servants - The Hebrew text in Joel is “upon the servants.” The Septuagint and the Latin Vulgate, however, render it “on my servants.” In Joel, the prophet would seem to be enumerating the different conditions and ranks of society. The influences of the Spirit would be confined to no class; they would descend on old and young, and even on servants and handmaids. The Septuagint and Peter evidently understood it in the sense of servants of God, as the worshippers of God are often called servants in the Scriptures. (See Rom. 1:1). It is possible, however, that Joel intended to refer to the servants of God. It is not “upon your servants,” etc., as in the former expression, “your sons,” etc.; but the form is changed, “upon servants and handmaids.” The language, therefore, will admit the construction of the Septuagint and of Peter; and it was this variation in the original Hebrew which suggested, doubtless, the mention of “my servants,” etc., instead of your servants.

And on my handmaids - Female servants. The name is several times given to pious women, (Ps. 86:16; 116:16; Luke 1:38, 48). The meaning of this verse does not materially differ from the former. In the times of the gospel, those who were brought under its influence would be remarkably endowed with ability to declare the will of God.

(Verse 19) - I will show wonders - Literally, “I will give signs”. The word in the Hebrew, means properly “prodigies; wonderful occurrences; miracles performed by God or his messengers,” (Exo. 4:21; 7:3, 9; 11:9; Deut. 4:34), etc. It is the common word to denote a miracle in the Old Testament. Here it means, however, a portentous appearance, a prodigy, a remarkable occurrence. It is commonly joined in the New Testament with the word “signs” - “signs and wonders,” (Matt. 24:24; Mark 13:22; John 4:48). In these places it does not of necessity mean miracles, but unusual and remarkable appearances. Here it is used to mean great and striking changes in the sky, the sun, moon, etc. The Hebrew is, “I will give signs in the heaven and upon the earth.” Peter has quoted it according to the sense, and not according to the letter. The Septuagint is here a literal translation of the Hebrew; and this is one of the instances where the New Testament writers did not quote from either.

Much of the difficulty of interpreting these verses consists in affixing the proper meaning to the expression “that great and notable day of the Lord.” If it be limited to the day of Pentecost, it is certain that no such events occurred at that time. But there is, it is believed, no propriety in confining it to that time. The description here pertains to “the last days” (Acts 2:17); that is, to the whole of that period of duration, however long, which was known by the prophets as “the last times.” That period might be extended through many centuries; and during that period all these events would take place. The day of the Lord is the day when God will manifest himself in a special manner; a day when he will so strikingly be seen in his wonders and his judgments that it may be called his day. Thus, it is applied to the day of judgment as the day of the Son of man; the day in which he will be the great attractive object, and will be signally glorified, Luke 17:24; 1 Thes 5:2; Phil. 1:6; 2 Pet. 3:12. If, as I suppose, “that notable day of the Lord” here refers to that future time when God will manifest himself in judgment, then we are not to suppose that Peter meant to say that these “wonders” would take place on the day of Pentecost, or had their fulfillment then, “but would occur under that indefinite period called “the last days,” the days of the Messiah, and before that period Was closed by the great day of the Lord.” The gift of tongues was a partial fulfillment of the general prophecy pertaining to those times. And as the prophecy was thus partially fulfilled, it was a pledge that it would be entirely; and thus there was laid a foundation for the necessity of repentance, and for calling on the Lord in order to be saved.

Blood - Blood is commonly used as an emblem of slaughter or of battle.

Fire - Fire is also an image of war, or the conflagration of towns and dwellings in time of war.

Vapour of smoke - The word “vapor”, means commonly an exhalation from the earth, etc., easily moved from one place to another. Here it means rising columns or pillars of smoke, and is another image of the calamities of war, the smoke rising from burning towns. It has always been customary in war to burn the towns of an enemy, and to render him as helpless as possible. Hence, the calamities denoted here are those represented by such scenes. To what particular scenes there is reference here it is impossible now to say. It may be remarked, however, that scenes of this kind occurred before the destruction of Jerusalem, and there is a striking resemblance between the description in Joel and that by which our Savior foretells the destruction of Jerusalem. (See Matt. 24:21-24). Some suppose that the reference in Joel may have been to the usual appearances of the sirocco, or that they may have suggested the image used here. It is said: “We have two kinds of sirocco, one accompanied with vehement wind, which fills the air with dust and fine sand. I have often seen the whole heavens veiled in gloom with this sort of sandcloud, through which the sun, shorn of his beams, looked like a globe of dull smouldering fire. It may have been this phenomenon which suggested that strong prophetic figure of Joel, quoted by Peter on the day of Pentecost. Wonders in the heaven and in the earth; blood, and fire, and pillars of smoke; the sun shall be turned into darkness, and the moon into blood. The pillars of smoke are probably those columns of sand and dust raised high in the air by local whirlwinds, which often accompany the sirocco. On the great desert of the Hauran I have seen a score of them marching with great rapidity over the plain, and they closely resemble ‘pillars of smoke.’”

(Verse 20) - The sun shall be turned into darkness – (See Matt. 24:29). The same images used here with reference to the sun and moon are used also there: They occur not infrequently, (Mark 13:24; 2 Pet. 3:7-10). The shining of the sun is an emblem of prosperity; the withdrawing, the eclipse, or the setting of the sun is an emblem of calamity, and is often thus need in the Scriptures, (Isa. 60:20; Jer. 15:9; Ezek. 32:7; Amos 8:9; Rev. 6:12; 8:12; 9:2; 16:8). To say that the sun is darkened, or turned into darkness, is an image of calamity, and especially of the calamities of war, when the smoke of burning cities rises to heaven and obscures his light. This is not, therefore, to be taken literally, nor does it afford any indication of what will be at the end of the world in regard to the sun.

The moon into blood - The word “blood” here means that obscure, sanguinary color which the moon has when the atmosphere is filled with smoke and vapor, and especially the lurid and alarming appearance which it assumes when smoke and flames are thrown up by earthquakes and fiery eruptions, (Rev. 6:12), “And I beheld when he had opened the sixth seal, and lo, there was a great earthquake, and the sun became black as sackcloth of hair, and the moon became as blood,” (Rev. 8:8). In this place it denotes great calamities. The figures used are indicative of wars, and conflagrations, and earthquakes. As these things are Matt. 24 applied to the destruction of Jerusalem; as they actually occurred previous to that event (see Matt. 24), it may be supposed that the prophecy in Joel had an immediate reference to that. The meaning of the quotation by Peter in this place therefore is, that what occurred on the day of Pentecost was the beginning of the surges of wonders that was to take place during the times of the Messiah. It is not intimated that those scenes were to close or to be exhausted in that age. They may precede that great day of the Lord which is yet to come in view of the whole earth.

That great and notable day of the Lord - This is called the great day of the Lord, because on that day he will be signally manifested, more impressively and strikingly than on other times. The word “notable,” means “signal, illustrious, distinguished.” In Joel the word is “terrible or fearful”; a word applicable to days of calamity, and trial, and judgment. The Greek word here rendered notable is also in the Septuagint frequently used to denote “calamity” or “times of judgment,” (Deut. 10:21; 2 Sam. 7:23). This will apply to any day in which God signally manifests himself, but particularly to a day when he shall come forth to punish people, as at the destruction of Jerusalem, or at the day of judgment. The meaning is, that those wonders would take place before that distinguished day should arrive when God would come forth in judgment.