Jismáél kenyéren és vizen

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And Avraham rose up early in the morning, and took bread, and a bottle of water, and gave it to Hagar, putting it on her shoulder, and the child, and sent her away: and she departed, and wandered in the wilderness of Be᾽er-sheva.

לחם וחמת מים BREAD AND A BOTTLE OF WATER — but not silver and gold, because he hated him for taking to degenerate ways (Exodus Rabbah 1:1).

But no silver and gold because he despised him... But according to the simple explanation [see Rashi on v. 11] he did not fall into bad ways. Why did Avraham not give him silver and gold? An answer is: Avraham assumed that shortly, after Sarah’s anger subsides, he will bring him back. (Maharshal) But according to R. Meir Stern’s explanation on v. 11, the question does not arise, because the simple explanation does not conflict with the Midrash. Both are needed; see there. Furthermore, Maharshal’s answer cannot be correct. For if it was, Rashi himself should have explained thusly, that Avraham intended to bring him back—as this would satisfy both the simple explanation and the Midrash. Rashi should not have given a reason that satisfies only the Midrash.

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וישכם אברהם בבוקר ויקח לחם וחמת מים, “Avraham rose early in the morning; he took bread and a skin-bottle of water, etc.” He should have given Hagar silver and gold and camels to transport both her, Ishmael, and their belongings seeing he had plenty of money to spare. After all, had he not prayed for his son’s welfare in 17,18 saying to G’d: לו ישמעאל יחיה לפניך, “if only Ishmael live (a good life) in Your presence?” However, seeing that Sarah had told him to expel Hagar and her son, and G’d had told him to obey everything that Sarah said to him (verse 12), Avraham complied and expelled them with the minimum of creature comforts plus a survival kit only. This is Nachmanides’ view.

One may view the fact that Avraham provided Hagar with bread and water as an allusion to something that he foresaw concerning the future when his descendants would be oppressed by the Arabs. He foresaw that the Ishmaelites would hate the Jews more than any other nation on earth hated them. Avraham was careful not to deny Hagar and Ishmael the necessities to ensure their survival, something with which Jews provide even their enemies. He modeled himself after Proverbs 25,21 “If your enemy is hungry feed him bread; if he is thirsty, give him water to drink.”

AND SHE CAST THE CHILD. Thirst overtook him and he was unable to walk, and so his mother laid him under the tree, cast away and abandoned. It may be that the word vatashleich (and she cast) is similar in sense to the verses: And He cast them into another land; Cast me not away from Thy presence, meaning “sending away.”
Rabbi Abraham ibn Ezra said: “And she cast for she had taken him onto her lap when he was weakened by thirst, [and seeing that he was expiring from thirst, she cast him from her].”
Our Rabbis have said that he was sick at the time he sent him away, and therefore he put the child on her shoulder. This is the sense of the word vatashleich (and she cast) him: [until that point she had carried him].
All this occurred to Abraham because he had been commanded to do whatever Sarah said, and she commanded that he send him away immediately, and it was at her command that he did not give them silver and gold, servants, and camels to bear them.