Rabbi Eliezer forbids purchasing a Parah Adumah – a Red Heifer used in the process of purifying someone who was ritually defiled because of contact with the dead (see Sefer Bamidbar chapter 19) – from a non-Jew. The Sage, Sheila, explains that Rabbi Eliezer’s ruling is based on his reading of the passage (Bamidbar 19:2) that commands that Jewish people must “take” the animal, which is understood to mean that they must take it from a fellow Jew.
This explanation is challenged because there are other similar passages, for example when the Torah commands that contributions be taken from the people to build the mishkan – the Tabernacle – the same language is used, yet we know that some of the components used in the Temple were purchased from non-Jews. The specific example referred to is the famous story of Dama ben Netina, a non-Jew in Ashkelon, who had stones that were needed for the breastplate of the High Priest. When the Sages came to purchase them his father was asleep and the keys to the safe were under his father’s pillow. Dama ben Netina chose to lose the opportunity for a lucrative business deal, rather than wake his father, a decision that so impressed the Sages that they used this story to illustrate how far a child must go to fulfill the commandment of “Honor your father and your mother.”
Dama ben Netina was one of the leading members of the non-Jewish community in Ashkelon during Second Temple times, and he served as one of the representatives on the city council. It appears that he was a very wealthy individual who was well-respected in his community and beyond. The story related in our Gemara is just one of many that appear in the Gemara describing the respect and honor that he showed his parents.