Psalm 89:34—”My covenant will I not break, nor alter the thing that is gone out of my lips.”
The Lord anointed David with the holy oil, not only as an emblem of the graces and gifts he received, but as the King Priest and Prophet anointed with the Holy Ghost without measure. The covenant with David was, “I will establish his offspring forever and his throne as the days of the Heavens.(Psalm 89:29)”. David after his anointing, was persecuted, but none could gain advantage against him. This relation is a perpetual one between David’s descendants and God. The Covenant of Grace made with Christ stands fast with Him, which is firm, sure, and stable, and as immovable as the mountains. He is a God who keeps His covenant with us, and will not break His Word with us: nor alter any thing that has gone out of His lips, such as, any Promise of God that respects either the temporal, spiritual, or eternal welfare of His people.
God does not pollute, defile, nor profane His Word. God said that He will not do in regard to the covenant just as the posterity of David had done. God does not change in His nature and perfections, nor in His love, or in His counsels and purposes. So, neither will God change His Covenant and Promises because they are always the same, and have a certain and unchangeable accomplishment. God, when He promises, respects His own mercy and not man’s power to perform something. God’s covenant, like His laws, is a sacred thing. Men may violate His laws, but God will not violate His covenant. The Word once spoken is irrevocable.
David is therefore, as Psalm 89:30 affirms, eternal in his seed; God will make David’s seed and throne into eternal, i.e., into such as will abide for ever. What is promised in Psalm 89:26 is a world-wide dominion, not merely dominion within the compass promised in the primeval times, nor does the promise, however, sound so definite and boundless, but it is indefinite and universal.
The promises of God are yes and amen. It’s in the Bible, 2 Corinthians 1:20 NJKV. “For all the promises of God in Him are Yes, and in Him Amen, to the glory of God through us.” It is in the hand of God, wise and gracious, who knows what He does and what is best. When Christ was on the cross, God seemed to have cast him off, yet did not make void His Covenant, for that was established for ever. There is a crown of glory reserved for Christ’s spiritual seed, which fadeth not away. None of God’s promises in the Bible ever fail. “…Not one word has failed of all the good things that the LORD your God promised concerning you. All have come to pass for you; not one of them has failed.”