Charles H. Spurgeon on Psalms 86:12

I will praise thee, O Lord my God, with all my heart. When my heart is one, I will give thee all of it. Praise should never be rendered with less than all our heart, and soul, and strength, or it will be both unreal and unacceptable. This is the second time in the psalm that David calls the Lord "my God", the first time he was in an agony of prayer (Ps 86:2), and now he is in an ecstacy of praise. If anything can make a man pray and praise, it is the knowledge into that the Lord is his God. And I will glorify thy name for evermore, eternity gratitude will prolong its praise. God has never done blessing us, let us never have done blessing him. As he ever gives us grace, let us ever render to him the glory of it.