My heart is fixed, O God - Margin, as in Hebrew, “prepared.” Compare the notes at Psalms 51:10. The word “suited” or “prepared” accurately expresses the sense of the Hebrew, and it is so rendered in the Septuagint, (ἑτοίμη hetoimē); in the Vulgate, “paratum;” and by Luther, “bereit.” The word is used, however, in the sense of “standing erect,” Psalms 9:7; to “establish” or “strengthen,” Psalms 89:4; Psalms 10:17; and hence, to be erect; to be firm, steady, constant, fixed. This seems to be the meaning here, as it is expressed in our common version. His heart was firm and decided. He did not waver in his purpose, or lean now to one side and then to the other; he was not “swayed” or “moved” by the events that had occurred. He felt conscious of standing firm in the midst of all his troubles. He confided in God. He did not doubt his justice, his goodness, his mercy; and, even in his trials, he was ready to praise him, and was “resolved” to praise him. The repetition of the word “fixed” gives emphasis and intensity to the expression, and is designed to show in the strongest manner that his heart, his purpose, his confidence in God, did not waver in the slightest degree.
I will sing and give praise - My heart shall confide in thee; my lips shall utter the language of praise. In all his troubles God was his refuge; in all, he found occasion for praise. So it should be the fixed and settled purpose of our hearts that we will at all times confide in God, and that in every situation in life we will render him praise.