John Calvin's Commentary on the Bible - Psalms 66:15
Verse 15 15I will offer unto thee burnt-sacrifices of fatlings. We must suppose the speaker to be either David or one of the more considerable men of the nation, for none in humbler circumstances could have offered rich sacrifices of this kind. It is probable that David was the author of the psalm, and here he signifies his intention to show a kingly liberality in his offerings. The reason why God ordered victims to be offered as an expression of thanksgiving was, as is well known, to teach the... read more
Adam Clarke's Commentary on the Bible - Psalms 66:19
Verily God hath heard me - A sure proof that my prayer was upright, and my heart honest, before him. read more