In this week's Parsha, Avraham Avinu (then called Avram) was chosen by Hashem to play a special role in humanity. The Parsha opens with Hashem's instructions for Avraham to leave the country of his birth, his relatives and father's house for a distant unknown land. Avram made preparations for the journey, and left with his wife, Sarai, and his nephew, Lot. But why was Avram picked? The Torah itself never discusses it.
A Midrash, however, relates the story of how Hashem picked Avram. Hashem approached one man from a certain nation and asked him if he would accept the Torah. The man requested to know some of its requirements. Hashem responded by saying that the Torah prohibits stealing. The man then declined because stealing was a way of life for him. So, Hashem moved on and approached a man from a different nation. He asked him if he would accept the Torah. The man asked what it contained. Hashem answered that the Torah prohibits murder. The man immediately declined because murder was a way of life for him. Hashem approached all the nations of the world and not one accepted for one reason or another. Later, he went to Avram and asked if he would accept the Torah. Avram agreed on the spot and Hashem gave him the instruction mentioned above.
The Rabbis write that only foolish people take Midrashim literally, however, only fools fully discount the literal interpretation of Midrash. So what about the Midrash above? The Midrash relates that the prevailing standards of morality in the world at Avram's time were at great odds with Torah values. Most people wouldn't have been able to abide by the standards of the Torah. Avram, however, was recognized by Hashem as a moral person and so he was chosen.
The Torah itself doesn't provide concrete specifics about Avram's early life and certainly doesn't discuss his ethics. Nevertheless, at the end of last week's Parsha the Torah provides a hint of Avram's (and his family's) ethics. It was written that Avram's father, Terach, had three sons: Haran, Nachor and Avram. Haran died and left his three children orphans. Terach, Avram and Nachor stepped in and took action and took care of Haran's children. Eventually, Nachor married Milcah and (Avram married Haran's daughter Sarai), Avram also takes his nephew Lot under his wing and continues to look out for his welfare even after the two, later on, part ways.
It is interesting to note that the women here are mentioned by name, unlike in many previous chapters of Bereishit. This shows the importance of the women in Terach and Avram's family. It foreshadows Avram's future partnership with Sarai in spreading the monotheistic faith.
The values Hashem was looking for were, in part, family values and Avram was the first to clearly exemplify them. Without these values, great Tzaddikim would be unable to transmit their beliefs and way of life to their children. Noach, Chanoch and Enosh, three of the earliest Tzaddikim, are examples of people who failed to transfer their beliefs to the next generation. Avram was chosen by Hashem, not only for his own outstanding qualities, but because he had the ability to transmit them (as shown through many examples later in the Torah) to the next generation.