This week we are privileged to read the portion of Matos. The portion begins with the laws pertaining to an oath. The Torah stresses the importance of every word one utters out of his/her mouth. Later in the portion we learn that two and a half tribes (Gad, Reuven and 1/2 Menashe), wished to stay on the other side of the Jordan. Moshe agreed to grant them the land which was captured from Sichon and Og on condition that they join their brethren in battle to capture Eretz Yisroel, and only afterward can they return to the other side of the Jordan River.
In Bamidbor 30/3 the Torah teaches us: one shall not desecrate his word, according to what comes out of his mouth, he shall do. The father of Reb Bunim of Parshischa explains this phrase as follows. Many times we get emotional and excited about doing something, for example charity for an important cause, and we make a pledge, however when it comes to fulfilling the pledge/obligation we are not as enthusiastic. This is what the Torah is telling us, just as it comes out of your mouth, so Should you DO. The enthusiastic feeling should be equal when you fulfill your commitment as it was when making it.
We find similar words repeated later in the portion and perhaps we can explain it on another level. Moshe tells the two and a half tribes (Bamidbor 32/24) build for yourselves cities for your children and gates for your flock and "what comes out of your mouth shall you do." Perhaps this portion is referring to the Jewish way of raising a family. We must create barriers around our children so that they don't get bad influences from the world, however we can only achieve that if we do what we demand of them. A father/mother who tells their child to do mitzvohs or to behave in a certain manner and he/she behaves differently it will not work. The gates you build will only be effective if you have the same borders. Do as you demand of your children. On a side note: Reb Elya Roth of Jerusalem, would say "raising children is like the egg under the chicken. The chicken must keep it warm and protect it from the outside environment, so that it can develop and become a chicken. However at the same time it must be careful not to apply to much pressure so that it won't brake." We must protect our children and provide them warmth and protection from the outside world. At the same time we must be cautious not to over pressure them, so that they don't become broken.