"A worker's appetite works for him, for his hunger urges him on"
This is an interesting passage because it states one of the ways that self-interest inside of each of us works for righteousness instead of against us.
This is the Hebrew word amel which means laborer or worker. The idea is one who labors to put food on the table for his family.
This is the Hebrew word nephesh and means soul, inner person. It is interesting that the translators chose to use the word appetite when really the word is soul. The inner man is what is being referred to rather than the pangs of his stomach.
It is the press of the inner man who has assessed the situation and made the determination that work must be performed or they will die. The inner man makes this calculation out of self-interest. It is not wrong to have self-interest. It is this self-interest that Jesus refers to when he quotes the second great commandment, "Thou shalt love thy neighbor as thy self." You must have a level of self-interest in order to meet other people's needs.
Selfishness is something different from self-interest. Selfishness is when only you are considered in the equation and when what you are pursuing will damage or harm others in its pursuit.
It is important to stop at this point and say that the person who plays the martyr and never thinks of themself or constantly endangers themself for the good of others is not a normal thing. Unless the Lord has specifically called a person to that type of situation because of persecution, a martyr complex or orientation in life is not right or healthy. It cuts away at the basic element of health which is self-love or self-interest. You need that to be in a position to give to others. Most people do not have this problem, but some do. They do not look after their own interests at all. They allow themselves to be destroyed or damaged in the process of aiding others. There are rare instances where that is called for but it is rare. The normal situation is what Solomon is talking about here, where your normal self-interest decides your basic needs and seeks to accomplish that so you can then give and care for others.
Think through this idea – you need a certain amount of food, a certain amount of money, a certain amount of space, a certain amount of education, a certain amount of relationships, a certain amount of drink just to be functioning normally and healthfully. Going after these normal limits is self-interest. It is not selfishness. It is selfishness when you pursue your desires beyond your needs. It is selfishness when you are willing to harm or damage others to get what you want.
I see this kind of struggle most often working in mothers. They are so much for their children that they will not take care of their own basic needs. Then if they push past their own needs long enough, they will be unable to healthily continue to give care for their children. The other issue is that they will inject into their children the terrible idea that everyone should serve them even to the point of exhaustion and/or unhealthfulness. Children must learn to care for themselves through the process of growing up. They need to be made to clean their room, take responsibility for their own actions, do their school work, etc. Does it really help a child if their mother over-sacrifices to the point where her health and or sanity is threatened? No. Now I am not saying that parents should not sacrifice for their children, but that sacrifice should come out of a basically healthy position.
This is the Hebrew word peh which means mouth. The soul recognizes that if food is not inserted in the mouth, then it will not be long before there is a separation of the soul and the body. The need of the mouth pushes on the person laboring for their food.
This is the Hebrew word akaph which means to press, urge. The idea is to exert pressure.
Back to Solomon's insight. The person who is working for that day's wage has an internal pressure from their soul to keep working so that they can meet their basic physical needs at the end of the day. This is a good thing and helps employers keep employees focused on the tasks that need to be done.
Solomon is saying the workers selfishness wants to lie down or cheat or steal, but their soul exerts pressure on them to stay with the work so that they can receive the money they need to purchase food and other basics. Their self-interest overcomes their selfishness.