O God, my heart is fixed - Prepared, suited, ready. See the notes at Psalms 57:7. In Psalms 57:7, this is repeated: “My heart is fixed; O God, my heart is fixed:” indicating that there “might” have been some doubt or vacillation caused by the circumstances then existing, and the repetition would have respect to that, as if the psalmist had been unsettled and wavering for a time, but was at last firm. In such circumstances it would not be unnatural to “repeat” the assertion, as if there were no longer any doubt. In the beginning of a psalm, however, where there had been no previous expression or feeling of doubt so far as appears, there would be no propriety in repeating the assertion.
I will sing and give praise - See the notes at Psalms 57:7.
Even with my glory - This is not in Psalms 57:1-11. It is literally here, “truly my glory.” In Psalms 57:8, however, the expression, “Awake up, my glory,” occurs, and this seems to correspond with that language. It means here that it was his glory - his honor - thus to be employed in giving praise to God. It was worthy of all that there was elevated in his nature; of all that constituted his glory; of his highest powers. At no time is man employed in a more noble and lofty work than praise.