ותרא שרה את-בן-הגר המצרית אשר-ילדה לאברהם מצחק: ותאמר לאברהם גרש האמה הזאת ואת-בנה כי לא יירש בן-האמה הזאת עם-בני יצחק
Sarah saw the son of Hagar, the Egyptian, who [she] had born to Avraham, playing. [Sarah] said to Avraham: “Expel this maidservant and her son, for the son of this maidservant shall not inherit with my son Yitzchak”
Reading a rudimentary translation of the Torah would yield quite a shocking result. Sarah sees Yishmael, the son of her maidservant Hagar and her husband Avraham, playing. Her response? Kick him out! How can Sarah be so harsh? She also says that Yishmael shall not inherit with Yitzchak. What does this have to do with his playing? This is why it’s so important to read the Torah in its original language.
The Torah uses the word מצחק, which is often translated as playing. However, Rashi tells us that it has more significant connotations. Often, we find the word מצחק associated with the three cardinal sins: idol worship, murder, and illicit relations. Rashi is telling us that the Torah’s choice of words here is precise. It’s to tell us that Yishmael was engaged in the worst sorts of behavior. Sarah was concerned that he would be a negative influence on her own son Yitzchak. She therefore felt justified that his presence be removed from her household.
We find a very interesting comment by Rabbeinu Avraham ben HaRambam. He explains the word מצחק almost literally. Sarah saw Yishmael behaving like a teenager. He was hanging out, wasting his time. He was using foul language. He wasn’t doing so much with his life. What was Sarah’s main concern? Rabbeinu Avraham says that she was concerned Yitzchak would hang out with him. Instead of perfecting his character, Yitzchak would waste an hour of his time. This is an astounding explanation. Why didn’t Rabbeinu Avraham say simply like Rashi? What’s the big deal if Yitzchak wastes an hour of his time?
We see from here an amazing principle. Sarah wasn’t concerned Yitzchak would sin. As bad as sinning is, there’s always the possibility of teshuva, sincere repentance. If Yitzchak would be negatively influenced by Yishmael, he could always mend his ways. What’s something that can’t be fixed? Wasted time. That time which could have been better spent can never be regained. It is this which Sarah feared most. She knew the secret that we sometimes forget, that time is precious, and is our most valuable commodity. We are given a limited amount of it in this world, and there are few who use it wisely.
 Based on Zahav Mishva to Genesis 21:9, by Rav Moshe Shmuel Shapira zt”l
 Genesis 21:9,10
 Ad. loc.
 Ad. loc.