Why did they suddenly decide to ask Rivkah for her opinion?
Rashi: Because one does not marry off a woman without first obtaining her consent. 1
Rashbam: Because in spite of Eliezer's reply, it was simple etiquette to ask Rivkah herself whether she would not prefer to wait, in compliance with their suggestion, and to leave in another year or so - even to travel with someone else if need be.
Seforno: They asked her whether she would agree to go with Eliezer (though he does explain why she might not).
Malbim: Because they were trying to delay the process through her, assuming that she would refuse to go with ?this slave?, and would rather want her family to accompany her.
In which they ought not to have agreed outright on the previous day.
QUESTIONS ON RASHI
Rashi writes: "We learn from here that we do not bring a woman to marriage without her consent." If so, how did Yitzchak marry Rivkah as a Ketanah? The Gemara (Kidushin 41a) forbids a father to accept Kidushin on his daughter's behalf, until she reaches majority and expresses whom she wishes to marry?
Gur Aryeh #1: This only applies when a father marries off his daughter (mid'Oraisa), but an orphan can be married off as a Ketanah, because she can subsequently leave the marriage through Mi'un if she so chooses. 1
Gur Aryeh #2: It was evident that HaSh-m had arranged this match (24:50), as shown by all the miracles that were involved, so there was no prohibition here at all.
Gur Aryeh: And Rivkah was now an orphan, for Besu'el had just died (Rashi to 24:55). But Eliezer had arranged the match even when he was still alive? A Nochri cannot accept Kidushin for his daughter, and Rivkah was akin to a Giyores [and in her own jurisdiction regarding Kidushin, akin to an orphan].
