This belongs to the group of psalms already referred to Ps. 146-150, each beginning and ending with a "Hallelujah," and probably composed after the return from the captivity, and the rebuilding of the walls of the city and the second temple. This psalm would be eminently appropriate to such an occasion - first, as expressing the joy of the nation; and secondly, as indicative of what the nation was to do in those circumstances in carrying out the purposes of God, and accomplishing his will. The people are considered as restored to their land; as safe, peaceful, happy; their city is securely fortified, and they are armed to defend themselves, and are now in a position to carry their conquests over the pagan and hostile powers around them. The psalm, therefore, consists of two parts:
I. The exhortation to praise, to joy, to rejoicing - as appropriate to their deliverance; to their safe return; to their re-establishment in their own land, Psalm 149:1-5.
II. The exhortation to carry out the purposes of God in regard to the people who had them, and who wronged were still hostile to them: to inflict on them the punishment which was due to them, and which God designed to bring upon them - regarding themselves as called of God to be his instruments in executing that punishment, in token of the divine displeasure at the conduct of those who had oppressed and wronged them, Psalm 149:6-9.

All the congregation are invited to praise God for his mercies, Psalm 149:1-3. Their great privileges, Psalm 149:4, Psalm 149:5. Their victories, Psalm 149:6-9.
This seems to be an epinikion, or song of triumph, after some glorious victory; probably in the time of the Maccabees. It has been also understood as predicting the success of the Gospel in the nations of the earth. According to the Syriac, it concerns the new temple, by which the Christian Church is meant. It has no title in the Hebrew, nor in any of the Versions, and no author's name.

INTRODUCTION TO PSALM 149
This psalm is thought by Calvin and others to have been written for the sake of the Jews that returned from the Babylonish captivity; and is a prediction of great and famous things done in the times of the Maccabees to Heathens and their princes, so Theodoret; the Syriac version entitles it,
"concerning the new temple;''
that is, the second temple, built by Zerubbabel, and the things done under that; but it rather seems to have been written by David in the beginning of his reign, when he obtained victories over the Philistines, Edomites, Moabites, Ammonites, and Syrians; and refers to the times of the Messiah, as Kimchi, R. Obadiah Gaon, and others think; not of the Jews' vainly expected Messiah, but of the true Messiah, who is come, and will come again, spiritually and personally; and there are many things in it applicable both to the first and latter part of his days.

(Psalm 149:1-5) Joy to all the people of God.
(Psalm 149:6-9) Terror to their enemies.

Hallelujah to the God of Victory of His People
This Psalm is also explained, as we have already seen on Psalm 147, from the time of the restoration under Ezra and Nehemiah. The new song to which it summons has the supreme power which Israel has attained over the world of nations for its substance. As in Psalm 148:14 the fact that Jahve has raised up a horn for His people is called תּהלּה לכל־חסדיו, so here in Psalm 149:9 the fact that Israel takes vengeance upon the nations and their rulers is called הדר לכל־חסדיו. The writer of the two Psalm is one and the same. The fathers are of opinion that it is the wars and victories of the Maccabees that are here prophetically spoken of. But the Psalm is sufficiently explicable from the newly strengthened national self-consciousness of the period after Cyrus. The stand-point is somewhere about the stand-point of the Book of Esther. The New Testament spiritual church cannot pray as the Old Testament national church here prays. Under the illusion that it might be used as a prayer without any spiritual transmutation, Psalm 149:1-9 has become the watchword of the most horrible errors. It was by means of this Psalm that Caspar Scloppius in his Classicum Belli Sacri, which, as Bakius says, is written not with ink, but with blood, inflamed the Roman Catholic princes to the Thirty Years' religious War. And in the Protestant Church Thomas M׬nzer stirred up the War of the Peasants by means of this Psalm. We see that the Christian cannot make such a Psalm directly his own without disavowing the apostolic warning, "the weapons of our warfare are not carnal" (2-Corinthians 10:4). The praying Christian must there transpose the letter of this Psalm into the spirit of the New Covenant; the Christian expositor, however, has to ascertain the literal meaning of this portion of the Scriptures of the Old Testament in its relation to contemporary history.