What did Avraham mean when he said, "Bil'adai"?
Targum Onkelus and Targum Yonasan: With reference to the previous Pasuk (where he refused to take anything from the king of Sedom), Avraham is now saying "with the exception of the booty that those who accompanied me to war took" - that, they would be permitted to keep. 1
Seforno: What he meant was, "Without my permission, [you can take everything, since I am not holding on to it anyway]!"
Riva: Avraham said that he does not know about those who accompanied him, whether or not they took.
What role did Aner, Eshkol and Mamrei play in the battle against the four kings?
Rashi: They guarded the camp while Avraham's disciples (or Eliezer) went to fight, therefore they would receive an equal portion of the spoils. 1
Seforno: Avraham claimed from the king of Sedom payment for what his youths had eaten, as well as their share of the booty, but Aner, Eshkol and Mamrei would be allowed to pick their own share of the booty, like captains.
Why did Avraham claim only what his youths had eaten?
It was called theft because the owners did not despair. Melech Sedom was chasing [to get it back]. Avraham did not give his youths a share of the spoils; they took it themselves.
Mishnas R. Aharon (Vol. 1, p.7): Legally, all the spoils belonged to Avraham, like Melech Sedom said. According to Avraham's level of Kedushah, however, it was considered consumed theft.
QUESTIONS ON RASHI
Rashi writes: "'The youths' - [i.e.] my servants; [and] the men who went with me..." What is Rashi adding?
Gur Aryeh: Rashi is clarifying that "the men who went with me " were not Avraham's servants who participated in battle (14:15), but rather an additional group.
Rashi writes: "Also Aner, Eshkol and Mamrei..."How does Rashi know that they were yet another distinct group that was to receive a share of the spoils?