"I will praise Thee, o Lord, with my whole heart" (Psalm 9:1).
"His praise shall continually be in my mouth" (Psalm 34:1).
"I will praise Thee forever" (Psalm 52:9).
First, David determines that he will praise the Lord. Then, he affirms continual praise. Finally, he declares that praise will be his portion forever.
Such adoration of God presupposes its source, namely, that God is good now, He will be good to us in every day of our earthly life, and and His goodness will abide throughout eternity. Indeed, will we ever encounter a present moment - such as this one - in which no basis for the praise of God exists? Hardly! We do well, in fact, to pause in this moment to each remember and affirm the wonder of our blessed Lord...
We also rejoice with David in the expectation of continual praise, based upon expressions of Divine goodness perpetually distributed to us. "Blessed be the Lord, who daily loadeth us with benefits, even the God of our salvation" (Psalm 68:19). David knew, as we must, that "every good gift, and every perfect gift is from above, and cometh down from the Father of lights." Moreover, he also realized that "in Him is no variableness, neither shadow of turning" (James 1:17). Thus, our Lord will continually abide in His determination to reveal unto and within us the glory of His beneficence. "Surely goodness and mercy shall follow me all the days of my life" (Psalm 23:6).
Finally, King David believed in the eternality of God's goodness, and thus, the eternality of adoration's proper and holy response. A long forever will not exhaust "the unsearchable riches of Christ" freely bestowed on all who trust the Lord Jesus. The Apostle Paul taught that "God hath raised us up together, and made us sit together in heavenly places in Christ Jesus, that in the ages to come He might show the exceeding riches of His grace in His kindness toward us through Christ Jesus (Ephesians 2:6-7). Think of it. Our Lord redeemed us for the sublime purpose of revealing His grace by forever being kind to us. We are as Mephibosheth of old, beckoned to the King's table solely because of relationship to our Jonathan, namely, the Lord Jesus (II Samuel 4). "God... hath blessed us with all spiritual blessings in heavenly places in Christ" (Ephesians 1:3). Forevermore, such goodness will grace the redeemed, and thus forevermore, the redeemed with have ongoing reason to declare the praise of God.
Praise now. Praise continually. Praise forever. Because of goodness now. Goodness continually. And goodness forever. This is the holy reception and response of God's trusting children in Christ, given freely to us for the glory of the Lord Jesus, and impacting every moment of both now and eternity. Now... continually... forever!
"I will sing praises unto my God while I have any being."