Two episodes occur in parshas Vayeira involving Avimelech, the king of the Pelishtim. When Avraham arrives in Avimelech's land, he takes Sara not realizing that she is a married woman. Later in the parsha he approaches Avaraham to enter into a treaty with him and Avraham confronts him concerning the wells Avimelech's servants had stolen. Although these two events appear unrelated, their similarities suggest that they be analyzed together.
Twice Avimelech is party to a sin which involves taking something from a fellow man. In the case of Sara, he takes a married woman away from her husband. His servants take wells away from their rightful owner. Both sins are fundamentally violations of mitzvos that govern our relationship with out fellow man; there doesn't appear to be anything "religious" in nature about either sin. When Avimelech is confronted with these violations, his response is almost identical in both cases. When Hashem appears to him accusing him of taking Sara, he responds that he is not to blame as he had no idea she was actually the wife of Avraham; he pleads ignorance. When he is confronted by Avraham regarding the theft of his wells, he again pleads ignorance, claiming that this is the first he has head of the theft.
Although the nature of the two accusations and Avimelech's defenses are almost identical, Avraham's response is different. Concerning the taking of Sara, Avraham tells Avimelech that what prompted the sin was the spiritual climate that existed in the land of the Pelishtim, "Rak ein yiras Elokim bamakom hazeh - there is no fear of Hashem in this place" (Breishis 20:11). However, after confronting Avimelech regarding the theft of the wells, Avraham doesn't elaborate on the root cause of this sin. Avraham has already identified the problem that led people to "mistakenly" take other's property, and thus there is no need to repeat this message. It was obvious that a society whose lack of fear of Heaven would allow for the taking of another's wife would also condone the stealing of another's wells.
How does "rak ein yiras Elokim" explain a sin that is an ethical breach in nature? Even without yiras Hashem one could presumably set up a society that respects other people's rights. With his response, Avraham dispels that notion. The root cause of an unethical society is the absence of yiras Hashem. Avimelech, as the king, was the one ultimately responsible for the spiritual character of his kingdom. It may have been true that he didn't realize that Sara was married and he didn't know about the theft of the wells, but it was the atmosphere devoid of yiras Hashem that enabled such things to occur. In a society permeated with yiras Hashem one need not fear that he will be killed so that his wife can be taken. In a culture of yiras Hashem it is inconceivable to steal another's wells. These two occurrences exposed the fundamental flaw in the kingdom of Avimelech for which he was held accountable.
Avimelech, as the ruler of a land lacking yiras Hashem, stands in contrast to Avraham who is described after akeidas Yitzchak to be a "yirei Elokim - one who fears Hashem" (Breishis 22:12). This praise of Avraham is especially significant in light of what Avraham personified. Avraham is singled out for his commitment "la'asos tzedaka umishpat - one who acts with righteousness and justice" (Breishis 18:19). The legacy of Avraham is one of gemilas chassadim - performing acts of loving-kindness to his fellow man. Yet, the crowning glory of Avraham is his being described as a yirei Elokim - one who fears Hashem. The Torah is giving us the correct perspective on interpersonal conduct. Ultimately, the only assurance of a commitment to justice and kindness is when these ideals are part of a commitment to yiras Hashem. If ethics and morality are defined by man, what today may be unethical may tomorrow become acceptable behavior. A society will only be a lasting, just, and kind one if it is rooted in yiras Hashem.
The best guarantee that Avraham would successfully transmit to his descendants his commitment "la'asos tzedaka umishpat" was his dedication to yiras Hashem. When his great-grandson Yosef is faced with his greatest challenge, he draws upon the legacy of Avraham. Responding to the temptation of the wife of Potiphar, Yosef first responds with an ethical argument, stating that to sin with Potiphar's wife would violate the trust he had in Yosef. Finally Yosef cries out, "v'eich e'eseh hara'ah hagedolah hazos v'chatasi l'Elokim - how could I do this great evil and sin against Hashem" (Breishis 39:9). The severity of this sin from the vantage point of a breach of trust against his fellow man is not sufficient to prevent this act. It is only the realization that this would be a sin against Hashem that serves as the ultimate deterrent.
Halacha identifies yiras Hashem as the guarantee for the veracity of testimony in beis din. Not only is one who sins against his fellow man not believed to testify truthfully, but even the otherwise "ethical" individual who violates prohibitions within the realm of bein adam lamakom - laws between man and Hashem - is disqualified from serving as a witness. Ethics which are not grounded in yiras Hashem cannot be guaranteed.
The survival of the legacy of Avraham can only be assured if it is adhered to in its entirety. Total dedication to the teachings of kindness and justice must be based on total commitment to yiras Hashem. It is only through this dual commitment that we can truly be the followers of Avraham Avinu.