James 3:18 - Joseph Benson’s Commentary on the Old and New Testaments

And the fruit of righteousness, &c. The principle productive of this righteousness, is sown, like good seed, in the peace of a believer's mind, and brings forth a plentiful harvest of happiness, (which is the proper fruit of righteousness,) for them that make peace That labour to promote this pure and holy peace among all men. Or, the meaning may be, they that endeavour to make peace among men, (which is a fruit or work of righteousness,) do thereby sow to themselves in peace; that is, they take that course which will produce to them happiness in the end.