Why did Eliezer tell Lavan about his private conversation with Avrohom?
(24,39) “And I said to my master: Perhaps the woman will not follow me”.
Rashi explains that the Hebrew word for “perhaps” (אולי) is written here without the letter ו, and so it could be understood to mean "to me", thus alluding to the fact that Eliezer had a daughter and he was trying to find a reason to get Avrohom to turn to him and marry Yitzchok to his daughter. But Avrohom said to him: My son is blessed and you are accursed, and one who is accursed cannot cleave to one who is blessed.
Behold, Rashi expounded this teaching from the fact that the word אולי is written without the letter ו, but this point is not brought in the Midrash, and it makes Rashi’s explanation problematic. Because earlier when Eliezer was speaking to Avrohom and said “Perhaps the woman will not want to follow me” (Bereishis 24,5) the word אולי is written with the letter ו. Why, according to Rashi, did the Torah delay the allusion to Eliezer’s desire to have his daughter marry Yitzchok until Eliezer related the events to Lavan, and not initially when he spoke these words to Avrohom?
But we can explain that the Torah did not tell us initially about Eliezer’s desire to marry into Avrohom’s family because what practical difference does this information make to us? But here the Torah wants to tell us about the faithfulness and guilelessness of Eliezer in carrying out Avrohom’s commision. Because when he saw from all that had happened that marriage with Rivkah had Hashem’s endorsement, he made every effort to persuade Lavan to let Rivkah marry Yitzchok.
Therefore he told him what he had said to Avrohom, that he wanted Yitzchok to marry his daughter and that Avrohom had negated the possibiltiy because one who is accursed cannot cleave to one who is blessed. But now Lavan had said to him “Come, the Blessed one of Hashem” (Bereishis 24:31) and the Midrash teaches that because Eliezer served Avrohom faithfully he ceased to be accursed and became one who is blessed. Therefore he could now entice Lavan to agree to the marriage by saying: If you do not want to make a marriage with Avrohom he will turn to me and take my daughter as a wife for his son. And since I am from his household and I know the man and his ways I am certainly in favor of such a marriage. And for the same reason you surely understand that he will prefer marriage with my daughter over your daughter.
From this we see the great faithfulness of Eliezer. That even though he was longer accursed and it was now possible for him to marry his daughter to Yitzchok, he nevertheless faithfully and guilelessly fulfilled the commission that Avrohom had charged him with.