Sing unto the Lord, praise ye the Lord
The prophet, from prayer, proceeds to praise; and from expressions of faith and confidence in the Lord, having committed his cause to him, being assured of success, rises up to a holy triumph and joy; and calls upon his soul, and upon others, to join with him in praising, and singing praises to the Lord: this is said, as Kimchi observes, with respect to the saints in Jerusalem; for there were some good people doubtless there at this time, a remnant according to the election of grace; who had a regard for the prophet, and wished well to him, and were ready to join with him in acts of devotion, prayer, or praise; for he hath delivered the soul of the poor from the hand of evil
doers;
or, "the life of the poor"; meaning himself, a poor destitute person, few or none to stand by him but the Lord, who had delivered him out of the hand of Pashur and his accomplices; and out of the hand of those that watched for his halting; and out of the hands of all his persecutors: or this may respect not past deliverances, but what was to come; which the prophet had such a believing view of, that he calls upon himself and others to praise God for beforehand.
The Brenton translation of the Septuagint is in the public domain.