This Maxim continues the theme of self-control that is found in some of the other Maxims. The phrases ‘wandering eye’ and ‘green-eyed monster’ are evidence of the fact that this particular type of self-control is necessary to comfortable living in society. The eye is one of the most important organs of sense and sages throughout time have remarked that it is the light of the body. This light has been equated with spiritual light as well as mere physical light.
It is self-control that determines the brightness of that spiritual light. It is self-control that allows us to be more than just unquiet spirits or physical beings. It is self-control that keeps our eye from focusing on the things we should not focus on, both outwardly and inwardly. Both the things that we look at that we should not and the emotions that they raise are things that we need to be aware of. And it is this self-awareness that is needed for the self-control we have been speaking about.
When we control ourselves and specifically when we control our ‘sight’ we create a greater ability to see the things we need to see. The ancients show us this fact in the other Maxims, and reinforce it with this one.