Gittin 59 - For peaceful co-existence
Young orphans may be hard-pressed to find sustenance. They may try to sell some of their land. But since all know that these children are not legally adults, and that when they grow up, they may retract and demand their field back, people may be unwilling to buy orphans' fields. Therefore the Sages changed the law here and allowed such sales to stand, even when the orphans grow up. At what age do young children acquire this right? -- Between six and ten, depending on their maturity.
In the synagogue on Shabbat seven people are called to read the Torah, and the first one should be the most learned. This law, however ancient and just, could lead to quarrel, and a new rule was adopted: the first one to read is a Kohen, and following him is a Levi. Afterwards a regular “Israel” Jews are called. In this way, people don't argue and peace prevails.
A similar law, established for peace in the society: if fish is caught in one's net, technically it does not belong to the owner of the net, because - if he does not hold the net - he has not acquired it in any of the accepted ways. Nevertheless, the Sages gave him the ownership, and now anyone else who takes the fish from the net is considered stealing it. Another law: gleanings in the field in Israel are left for the Jewish poor. Yet the Sages accepted the law that any poor who comes to collect them is permitted to do so - to prevent strife.
Art: The care of orphans By Jan De Bray