Matthew Henry's Concise Commentary

4:4-6 Solomon notices the sources of trouble peculiar to well-doers, and includes all who labour with diligence, and whose efforts are crowned with success. They often become great and prosperous, but this excites envy and opposition. Others, seeing the vexations of an active course, foolishly expect more satisfaction in sloth and idleness. But idleness is a sin that is its own punishment. Let us by honest industry lay hold on the handful, that we may not want necessaries, but not grasp at both hands full, which would only create vexation of spirit. Moderate pains and gains do best.