David, in confidence of faith and experience of God's favour, prayeth both for himself, and against the enemies of his soul: he promiseth constancy: he prayeth for perseverance: he praiseth God, and promiseth to do it cheerfully.
This psalm is so similar to the former, that, perhaps, says Mr. Mudge, as it is without a title, it is a continuation of that psalm: The author acknowledges the continued series of God's goodness to him, even from his birth, and implores him not to leave him now in his old age to the malice of his enemies, but to grant him his protection. Towards the end he is assured of this, and at length obtains it, and praises God for it. The Jews who were carried captive into Babylon, with king Joachim, made use of this psalm, as appears from the title of the Vulgate and LXX. See Psalms 31.