I will bless the Lord at all times; his praise shall continually be in my mouth.
Here is how Charles Spurgeon comments on this verse in the collection The Treasury of David:
“His praise shall continually be in my mouth,” not in my heart merely, but in my mouth too. Our thankfulness is not to be a dumb thing; it should be one of the daughters of music. Our tongue is our glory, and it ought to reveal the glory of God. What a blessed mouthful is God’s praise! How sweet, how purifying, how perfuming! If men’s mouths were always thus filled, there would be no repining against God, or slander of neighbours. If we continually rolled this dainty morsel under our tongue, the bitterness of daily affliction would be swallowed up in joy. God deserves blessing with the heart, and extolling with the mouth – good thoughts in the closet, and good words in the world. (Volume 1, pp. 122-123)
HT: Fighter Verses