For thou, O God, hast heard my vows - That is, my prayers accompanied with solemn pledges or promises that I will devote myself to thy service. In some way David had the assurance that those vows and prayers had been heard; that God would answer his supplications - that he would restore him to his home, and to the privilege of uniting with others in the sacred services of the sanctuary. In what way he had this assurance we are not informed, but the statement here accords with what we often find in the Psalms. His troubled mind became calm, for he looked upon the blessing as already granted. He entertained no doubt that what he had asked would be bestowed. The mind of a true believer often feels this assurance now. Somehow he feels an undoubting persuasion that the prayer which he has offered has been heard; that God will be merciful; that the blessing which has been sought will assuredly be conferred. That there may be danger of illusion here, no one can doubt - for we are not, as David was, inspired; but no one can prove that God may not impart such a gracious assurance to the soul; no one can show that it is wrong for a believer to allow peace to flow into his soul, in the confident hope that the blessing which he had sought will be his.
Thou hast given me the heritage of those that fear thy name - The heirship which pertains to such; the privileges of those who are the true children of God. One of these privileges is that of prayer; another is the peace which results from adoption into the family of God; of feeling that we are his heirs. Compare the notes at Romans 8:16-17.