Fences

The Bible commands the owner of a home with a flat roof to put up a ma’akeh - a fence - around the roof, so that blood will not be on the owner’s hands (Deuteronomy 22:8). Sefer Hachinukh , an anonymously written book about the 613 commandments (13th century) explains the underlying principle of the command to build a ma'akeh (Commandment 546): In our lives it is imperative that we take nothing for granted as far as safety goes. Some people are blessed with nine lives like the proverbial cat. Nevertheless, relying on miracles is not the Jewish way, so we must do our part to secure our lives by putting up safety barriers and not taking any unnecessary risks.

To cite two examples, the Chinukh warns against drinking directly from a lake or river because of the danger of drinking a leech. (Nowadays we are concerned with pollution as well, so we, the well informed, may not need such a warning.) We are also cautioned against putting money into one's mouth, simply because one never knows who has come in contact with the money (or what kind of bacteria).

While most people today no longer have flat roofs or homes with roof access that would require a ma’akeh, the modern day equivalent of this mitzvah might be putting bars or safety locks on upper story windows and erecting fences with locked gates around swimming pools.

The spirit of this law warns against damaging and doing harm to our bodies and to others.