My heart is fixed, O God,.... Firm and sure, trusting in the Lord, believing that he should be saved by him out of his troubles; see Psa 101:1. So, in a spiritual sense, a heart fixed and established, or that is firm and sure, is one that is assured of its salvation by Christ, rooted and grounded in the love of God, firmly built on the foundation, Christ, and has its affections set on him; and is unmoved, from the hope of the Gospel, and the doctrines of it, by whatsoever it meets with in the world. It may be rendered, "my heart is prepared", or "ready" (r); that is, according to some, to receive good or evil, prosperity or adversity, at the hand of God; to which sense is Jarchi's note, "my heart is faithful with thee in the measure of judgment, and it is faithful with thee in the measure of mercy.'' That is, whether I am chastised with judgments, or followed with mercies, my heart is firm and true to God. The Targum is, "my heart is prepared for thy law, O Lord; my heart is prepared for thy fear;'' that is, it is prepared for the worship and service of God; it is ready to every good work; it is prepared to pray unto him, and to wait for an answer, which are both from the Lord, Pro 16:1; and particularly to sing praise unto him, as follows; my heart is fixed; this is repeated, to show the vehemency of his spirit, and the certainty of the thing; I will sing and give praise; for the salvation wrought for him, and which he was sure of; and before he had finished this psalm, or while he had composed it, did enjoy it. (r) "paratum", V. L. Pagninus, Montanus, &c.