57. Thou art my portion, O Jehovah! The meaning of this clause is doubtful, because the term Jehovah may be rendered either in the nominative or vocative case, and the phrase, I have said, may relate either to the former or latter part of the verse. One lection then is, Jehovah is my portion, and, therefore, I have resolved to observe thy law. Another is, O God! who art my portion, I have resolved to observe thy law. A third is, I have said, or have resolved, that God is my portion, in order to observe his law. A fourth is, I have said, or have resolved, O Lord! that my portion is to observe thy law; and this is the reading of which I approve. The following interpretation is quite applicable, That God being our portion, ought to animate and encourage us to observe his law. We have already noticed in several other passages, that God is denominated the heritage of the faithful, because he alone is sufficient for their full and entire happiness. And seeing he has chosen us for his peculiar possession, it is only reasonable on our part, that we should rest satisfied with him alone; and if we do this, our hearts will also be disposed to keep his law and, renouncing all the lusts of the flesh, our supreme delight, and firm resolution, will be to continue in the same.
I have already said, that this exposition is not inconsistent with the scope of the passage, and that it furnishes a very useful doctrine. But the last and fourth reading, of which I remarked I approved, is more simple, — I am fully persuaded that my best portion consists in keeping God’s law; — and this accords with the saying of Paul, “Godliness is the best gain,” (1 Timothy 6:6). David here draws a comparison between the keeping of the law, and the imaginary good which captivates the ambition of mankind. “Let every one covet what seems to him good, and revel in his own pleasures; I have no ground to envy them, provided I retain this as my portion, the complete surrender of myself to the word of God.”