Charles H. Spurgeon on Psalms 138:2

Thou hast magnified thy word above all thy name. His "word" being here annexed to "lovingkindness and truth", must needs be that part of his word to which these two are applicable, i.e., his promise, the matter whereof is mercy or lovingkindness, and in the performance of which is truth or fidelity. And then to "magnify" this "word" of promise seems to signify two things; 1, the making very great and excellent promises, and then, 2, the performing them most punctually; and the doing it above all his name is promising and performing most superlative mercies above all that is famed or spoken or believed of God. Then thus it will run; I will worship, etc., "and praise thy name above thy lovingkindness and above thy truth"; i.e., it will be too low, too short a compilation, to call thee merciful or veracious, or style thee after any other of thy attributes; thou art all these, and more than so, "thou hast magnified thy word", given and performed most glorious promises, "above all thy name", above all that men have apprehended or spoken of thee. This verse and Psalm may easily be interpreted of God's mercies in Christ, so far above what could be famed, or said, or believed, or apprehended of him. —Condensed from H. Hammond.