In parashas Chayei Sarah, we are briefly introduced to Efron. He merits mention in the Torah only because he owned the Cave of Machpelah, in which Avraham wanted to bury his wife.
The Torah outlines the negotiations between the two over this piece of land. Initially Efron seemed quite magnanimous: Avraham wanted only the cave, but Efron offered him the field as well. Moreover, while Avraham was willing to pay for the cave, Efron offered to give it to him as a gift. However, when Avraham showed him the money, suddenly Efron changed his tune, saying, “My lord, heed me: land worth four hundred silver shekels – between me and you – what is it? Bury your dead.” The commentaries explain that Efron was hinting that he did indeed want Avraham to pay this exorbitant price for the field and cave. Avraham took the hint and paid the full amount.
Ramban is unsure whether Efron’s initial magnanimity was genuine. However, the Alter of Kelm, ztz”l, assumes it was. So how could Efron change so quickly from generosity to greed? The Alter answers with the following incident:
Rambam had a disagreement with the non-Jewish scholars. They believed one could train an animal to act with the same level of sophistication as human beings. Rambam maintained that it was impossible to change an animal’s nature.
The scholars sought to prove their point by training a cat to be a waiter. After several weeks of training, they proudly assembled a large group of people, including Rambam himself, to view the wonderful spectacle. The cat lived up to expectations. It set the table and greeted each person with great honor. Then the cat went to bring a bottle of wine to serve his guests. Suddenly Rambam opened a small box, and out jumped a mouse. As soon as the cat saw the mouse, it dropped the bottle, and all the wine spilled everywhere. “Resigning” as waiter, the cat ran to catch the mouse! Everyone admitted that Rambam was right and that it was impossible to change a cat’s nature. All they could do was teach it to act in a civilized fashion as long as there was no mouse around, but as soon as it saw the mouse, all its natural tendencies came flooding back.
The Alter identified the same phenomenon with regard to Efron. As long as he did not see the money, he was able to magnanimously give Avraham the field and cave. However, once he heard those coins jingle, his natural love of money overtook him. In a split second, Efron became a different person, losing any desire to help the great Avraham.
The example of Efron teaches a vital lesson. If a person does not work on his inherent character flaws, making great efforts to change, he may be able to bury them temporarily, but when his “mouse” appears, he will immediately fall back into his old ways.
Notes and Sources
 See Bereishis 23.
 Ramban, Bereishis 23:10.
 Bereishis, 23:11.
 Ibid. 23:15.
 Darkei Musar, Chayei Sarah, p. 54.
From the book “Beacons of Light”