Depart from evil, and do good - Seeing the above is so, depart from all evil - avoid all sin; and let not this be sufficient, do good. The grace of God ever gives this two-fold power to all who receive it; strength to overcome evil, and strength to do that which is right.
Depart from evil, and do good - This is the sum of all that is said in the psalm; the great lesson inculcated and enforced by all these references to the effects of good and evil conduct. All these results - all that people experience themselves, and all the effects of their conduct on their posterity, enforce the great practical lesson that we should do good and avoid evil. These results of conduct are among the means which God employs to induce men to do right, and to abstain from what is wrong.
And dwell for evermore - That is, dwell in the land: meaning (in accordance with the general drift of the psalm) that righteousness will be connected with length of days and with prosperity; that its effects will be permanent on a family, descending from one generation to another. See the notes at Psalm 37:3.