O give thanks unto the LORD. For He is good. Because His mercy endureth for ever. (Psalm 118:1)
For He is good.
This is reason enough for giving Him thanks; goodness is His essence and nature, and therefore He is always to be praised, whether we are receiving anything from Him or not. Those who only praise God because He does them good should rise to a higher note and give thanks to Him because He is good.
In the truest sense, He alone is good, "There is none good but one, that is God"; therefore in all gratitude the Lord should have the royal portion. If others seem to be good, He is good. If others are good in a measure, He is good beyond measure. When others behave badly to us, it should only stir us up the more heartily to give thanks unto the Lord because He is good; and when we ourselves are conscious that we are far from being good, we should only the more reverently bless Him that "He is good."
We must never tolerate an instant's unbelief as to the goodness of the Lord; whatever else may be questionable, this is absolutely certain, that Jehovah is good; His dispensations may vary, but His nature is always the same, and always good. It is not only that He was good, and will be good, but He is good; let His providence be what it may. Therefore let us even at this present moment, though the skies be dark with clouds, yet give thanks unto His name.
CH Spurgeon (from The Treasury of David)