Charles H. Spurgeon on Psalms 119:89

For ever, O LORD, thy word is settled in heaven. The strain is more joyful, for experience has given the sweet singer a comfortable knowledge of the word of the Lord, and this makes a glad theme. After tossing about on a sea of trouble the Psalmist here leaps to shore and stands upon a rock. Jehovah's word is not fickle nor uncertain; it is settled, determined, fixed, sure, immovable. Man's teachings change so often that there is never time for them to be settled; but the Lord's word is from of old the same, and will remain unchanged eternally. Some men are never happier than when they are unsettling everything and everybody; but God's mind is not with them. The power and glory of heaven have confirmed each sentence which the mouth of the Lord has spoken, and so confirmed it that to all eternity it must stand the same, settled in heaven, where nothing can reach it. In the former section David's soul fainted, but here the good man looks out of self and perceives that the Lord fainteth not, neither is weary, neither is there any failure in his word.

The verse takes the form of an ascription of praise: the faithfulness and immutability of God are fit themes for holy song, and when we are tired with gazing upon the shifting scene of this life, the thought of the immutable promise fills our mouth with singing. God's purposes, promises, and precepts are all settled in his own mind, and none of them shall be disturbed. Covenant settlements will not be removed, however unsettled the thoughts of men may become; let us therefore settle it in our minds that we abide in the faith of our Jehovah as long as we have any being.