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, Psalms 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, Psalms 149:6-9.