Why does the Torah go out of its way to inform us that Noach had three sons? Couldn't it have simply listed their names and we could have counted them for ourselves? As a matter of fact, the Torah does just that at the end of last week's parsha when it delineates Noah's genealogy. Why provide us with this unnecessary number?
Rabbi David Feinstein points out that the Talmud asks a similar question regarding the two sacrificial goats that are brought for the special Yom Kippur service in the Temple. There is a general grammatical rule of thumb in the Torah that when no number is attached to a plural noun, then it refers to two of that item. If this is the case, then why does the Torah, in Leviticus 16:5, go out of its way to say that two goats were necessary for the offering?
The Talmud derives from this superfluous mentioning of the number two that the sacrificial requirement must refer to a pair, that the goats have to be like twins - similar in worth and appearance - in order to be used for the Yom Kippur service.
Continuing this line of reasoning, it would seem that the seemingly unnecessary mentioning of the number three regarding Noah's sons is referring to the fact that they were triplets.
But that is simply not the case. Shem, Cham, and Yafet were born in different years, and were therefore not triplets. Rabbi Feinstein elucidates the matter by explaining that all three sons were created equally, all of them possessing the potential to be great men and inherit their father's good character traits.
However, we see that each son ended up differently. Shem was the only one that actually emulated his father's righteous ways. Yafet, and especially Cham, allowed themselves to be affected by the evil behaviors of the environment which surrounded them. Lest we mistakenly think that they all did not share the opportunity for stardom, the Torah informs us that initially they all started out as the three sons of Noah, all of them equal to one another.
This explanation of the verse presents us with a powerful lesson for our everyday lives. We cannot let the corrupt social values that we encounter seep into our souls. We must stay strong like Shem, and overcome any obstacles which may come in our way, so that we can successfully reach our goals and fulfill our potential to be the absolute best human being that we can be.