Charles H. Spurgeon on Psalms 145:1

I will extol thee, my God, O king. David as God's king adores God as his king. It is well when the Lord's royalty arouses our loyalty, and our spirit is moved to magnify his majesty. The Psalmist has extolled his Lord many a time before, he is doing so still, and he will do so in the future: praise is for all tenses. When we cannot express all our praise just now, it is wise to register our resolution to continue in the blessed work, and write it down as a bond, "I will extol thee." See how David testifies his devotion and adherence to his God by the pronoun "my", how he owns his allegiance by the title "king", and how he goes on to declare his determination to make much of him in his song. And I will bless thy name for ever and ever. David determined that his praise should rise to blessing, should intelligently spend itself upon the name or character of God, and should be continued world without end. He uses the word "bless" not merely for variation of sound, but also for the deepening and sweetening of the sense. To bless God is to praise him with a personal affection for him, and a wishing well to him: this is a growingly easy exercise as we advance in experience and grow in grace. David declares that he will offer every form of praise, through every form of existence. His notion of duration is a full one —"for ever" has no end, but when he adds another" ever" to it he forbids all idea of a close. Our praise of God shall be as eternal as the God we praise.