“the Hebrew.” This is the first use of “Hebrew” in the Bible.
“was living.” Abraham lived in a tent and had many servants who watched his flocks and herds, and they would have also lived in tents with him, so this was a typical Bedouin tent encampment, with dozens of tents. Genesis 12:16 says that Abram had flocks, herds, donkeys, camels, and both male and female servants (more likely a mixture of slaves and servants. The Hebrew word can be used of either a servant or a slave, so readers have to tell from the context whether “servant” or “slave” is meant). We learn from Genesis 14:14 that Abram had 318 men who were fighting age who had been “born in his house,” that is, as part of his household of slaves and servants, so he had a huge camp. Thus Abram was a powerful Bedouin chief. As the weather changed and grazing needs changed, the camp would move. This way of life is almost gone today, although a few Bedouin tribes that camp are left.
“of Mamre the Amorite.” “Mamre” was the name of a person and a place (Gen. 13:18). It is possible and even likely that the place was named after its early owner, Mamre.