Комментарий к Берешит 24:19

עד אם כלו literally, UNTIL THAT THEY HAVE FINISHED [DRINKING] — Here the word אם is used in the sense of אשר “that”. The words אם כלו the Targum renders by "That they have done enough drinking”. Though the verb כלה signifies to finish, to end, the Targum is right in translating it thus for this is the end of their drinking when they have drunk as much as they wanted (cf. Rashi on Genesis 43:2).

ותכל להשקותו ותאמר, she waited with speaking until Eliezer had finished drinking his fill. She followed the dictum of our sages that one should not engage in conversation while eating (during the meal) (Taanit 5)

ותכל להשקותו, When she completed giving him to drink, etc. Seeing that the Torah does not describe Eliezer as having finished drinking, it is clear the Torah wants us to know that she kept bringing him water until he stopped drinking.

ותכל...עד אם כלו לשתות, she meant that she would continue drawing water for the camels until she could ascertain that they would stop drinking. Alternately, the word אם is a substitute for the word אשר.

ותאמר גם לגמליך אשאב, she said: “I will also draw water for your camels.” The physical strength required for Rivkah to draw water for all of Eliezer’s camels could only be explained if she enjoyed divine assistance. This is all the more so if we accept the opinion of the sages in the Seder Olam that at that time Rivkah was only three years old. The whole matter can be viewed only as part of the success of which Avraham had assured Eliezer at the outset when he told him: “He will send His angel ahead of you and make your mission successful.” (24,7) This is the reason you find an allusion to G-d’s great name in our verse the name we have discussed in the previous paragraph. The fact that the letter ג in the word גמליך has a dagesh is additional evidence of an allusion to the attribute of גבורה being involved in what transpired at this well.

Because that is the end of their drinking—when they have had enough to drink. Accordingly, כלו is not from כלייה (“finished off”), as the Targum for that word is גמירא.

It is also possible that Rebeccah judged when Eliezer should stop drinking, seeing that weary travellers who have gone without water for a long time are not the best judges of when they may be drinking more than is good for their health.

We may view the matter also in light of what the Talmud teaches in Berachot 40, based on Deuteronomy 11,15 that one must feed one's animals before eating oneself. This ruling applies only when there is no danger to the life of the person involved. If his life is in danger, concern for his own health takes precedence over the wellbeing of his animals. When Rebeccah heard Eliezer ask for some water she concluded that she faced a man whose need for water was immediate. This is why she said to him: "drink!" As soon as she had given him sufficient water to ensure he was not in danger of dehydrating she suggested giving water to his camels, the ones which normally should have been looked after first. This is why the Torah phrases Rebeccah's action in such a way that we understand that as soon as was practicable she turned her attention to the camels, giving them to drink. She added that she would continue until the camels had finished drinking, meaning that in the case of the camels she was not going to rely on her personal judgment of when the animals had had enough to drink. She kept drawing water for the camels until they stopped drinking.