These verses require a little unpacking. The point is not to stick to yourself and be self-centered, it has another recommendation.
Proverbs 5:15-17: “15 Drink water from your own cistern,
running water from your own well.
16 Should your springs overflow in the streets,
your streams of water in the public squares?
17 Let them be yours alone,
never to be shared with strangers.“
A Source of Goodness
There are many reasons to drink from your well. You know the source of your drink and are used to it. Thus, surprises and illnesses are less likely. Your body is also accustomed to the water and not likely to receive a shock to the system from a drink. This applies far beyond what we drink and its source. Our lives are unique, and we have built tolerances as well as comfort within our life. When we stray away from what is ours, we open our life up to risk. Sometimes this is called going outside of our comfort zone.
We may wander outside of our comfort zone to grow our experiences. This Proverb is more about going outside of your comfort zone to keep up with the neighbors. This is a warning against desiring the possessions or the life of others. We have enough to worry about in our own lives. There is no benefit in trying to find happiness elsewhere.
The Public Square
The next bit is why I see this as more about desiring what others have than other translations. The warning against sharing with strangers strikes me as a warning against bragging. When you brag or show off what you have that may entice others to steal from you. This may be direct theft or indirectly. A good example is how the “rich” are often asked to “pay their share.” Thus, when you visibly have plenty, it makes you more likely to be a target in many ways. Think of the lottery winner that suddenly has a large number of friends. It seems to be a part of our nature to want to take advantage of those more successful than we are.
Teaching Children this Wisdom
This bit of wisdom is most easily shown with a little bait and switch. A simple example is to suggest a trip on a Saturday afternoon. If it is a boring location, the child will want to skip the journey. If one child goes and gets a pack of gum and another stays home, all is well. However, if the one with the gum brags about it, then the child that missed out will start complaining about fairness and ask for some gum. The child with the gum had water overflowing. Likewise, the other looked for it to be shared. Not exactly strangers, but a straightforward and easy way to teach this lesson.