Musar zu Bereschit 24:30

Laban was possessed of עין רע, he was ill-willed, begrudging, he was haughty and greedy. His whole concern in approving the match was to secure personal gain. The Torah is careful to document how Laban was motivated by money when we are told: "As soon as Laban saw the nosering and bracelets on the hands of his sister etc.,… he ran towards the man" (24,30). Laban was a swindler to boot. Realising that Eliezer had come to propose a שידוך, a match, he whispered to Eliezer that in consideration of an appropriate amount of money he would side with him and approve the match. Should Eliezer refuse, he, Laban would oppose the match; he was the most influential member of the household. When the Torah reports that "Laban had heard the words of Rebeccah his sister," this is our clue that he knew that a match was going to be discussed. Eliezer had no option but to promise Laban what he had asked. The reason the Torah does not report all this is because it simply never came to this. Eliezer did not keep his promise, as I shall explain. In his dealings with Laban Eliezer applied the principle of עם עקש תתפתל, "with the perverse you have to be wily" (Psalms 18,27). He did this by making a promise he would not keep. Laban was misled, for he believed that Eliezer would keep his part of the bargain.