For I have said - The Septuagint and the Latin Vulgate render this, "Thou hast said," which is more in accordance with what the connection seems to demand; but the Hebrew will not admit of this construction. The true meaning seems to be, that the psalmist had said; that is, he had said in his mind; he had firmly believed; he had so received it as a truth that it might be spoken of as firmly settled, or as an indisputable reality. It was in his mind one of the things whose truthfulness did not admit of a doubt.

Mercy shall be built up for ever - The mercy referred to; the mercy manifested in the promise made to David. The idea is, that the promise would be fully carried out or verified. It would not be like the foundation of a building, which, after being laid, was abandoned; it would be as if the building, for which the foundation was designed, were carried up and completed. It would not be a forsaken, half-finished edifice, but an edifice fully erected.

Thy faithfulness shalt thou establish - In the matter referred to - the promise made to David.

In the very heavens - literally, "The heavens - thou wilt establish thy faithfulness in them." That is the heavens - the heavenly bodies - so regular, so fixed, so enduring, are looked upon as the emblem of stability. The psalmist brings them thus before his mind, and he says that God had, as it were, made his promise a part of the very heavens; he had given to his faithfulness a place among the most secure, and fixed, and settled objects in nature. The sun in its regular rising; the stars in their certain course; the constellations, the same from age to age, were an emblem of the stability and security of the promises of God. Compare Jeremiah 33:20-21.

Mercy shall be built up for ever - God's goodness is the foundation on which his mercy rests; and from that source, and on that foundation, acts of mercy shall flow and be built up for ever and ever.

Thy faithfulness shalt thou establish - What thou hast promised to do to the children of men on earth, thou dost register in heaven, and thy promise shall never fail.

For I have said,.... That is, in his heart he had said, he had thought of it, was assured of it, strongly concluded it, from the Spirit and word of God; he believed it, and therefore he spoke it; having it from the Lord, it was all one as if he had spoke it:

For I have {b} said, Mercy shall be built up for ever: thy faithfulness shalt thou {c} establish in the very heavens.

(b) As he who surely believed in heart.

(c) As your invisible heaven is not subject to any alteration and change: so shall the truth of your promise be unchangeable.

89:2 Establish - As firmly and durably as the heavens themselves.

2. I have said-expressed, as well as felt, my convictions (2Co 4:13).

89:1-4 Though our expectations may be disappointed, yet God's promises are established in the heavens, in his eternal counsels; they are out of the reach of opposers in hell and earth. And faith in the boundless mercy and everlasting truth of God, may bring comfort even in the deepest trials.