Then shalt thou understand righteousness and judgment
This is another fruit and effect of the Gospel, and of a spiritual understanding of it; that besides the knowledge of God, and how to behave with reverence towards him, ( Proverbs 2:5 ) ; it leads men into a notion of doing that which is right and just among men; it gives them not only a theoretic but a practical understanding of justice, and a true judgment of what is right and wrong; or gives such an understanding thereof as that they practise it; for it teaches men to live soberly, righteously, and godly, ( Titus 2:11 Titus 2:12 ) . It is not only a revelation and ministration of the righteousness of Christ as the only matter of a sinner's justification before God; and informs a man's judgment so that he can distinguish between truth and error, right and wrong, good and bad notions and practices; but it influences his actions, life, and conversation, and engages him to do works of righteousness from the best principles, upon the best motives, and with the best views; and equity; [yea], every good path;
that is, so to understand equity, as to do that which is equitable between man and man; and to understand every good path which the word of God directs to, even all the commandments and ordinances of the Lord, so as to walk in them; these things the Gospel acquaints men with, and urges them to observe: or the words may be rendered, either "the rectitude" or "equity of fall good paths", as the Syriac version; how just, and right, and plain, and equitable, everyone is, and therefore ought to be walked in; or "plainnesses", or "most plain", is or shall be "every good path" F18, to them that have a spiritual and experimental knowledge of the Gospel; and by it an understanding of their duty. One word signifies "plain" and "straight", and another "round" F19, and both are true of the path of righteousness; for though it is a circle of duty saints walk in, yet straight and plain.
The Brenton translation of the Septuagint is in the public domain.