1)
Why did Eliezer pray? Did he not trust in Avraham's merit?
1.
Ohr ha'Chayim: He trusted that HaSh-m would send an angel in the merit of Avraham, but was unsure if he was worthy that the matter would succeed through him.
2)
What is the meaning of the word "Hakrei"?
1.
Malbim: 'Koros' are unexpected matters. Yaakov's sons told him "ha'Koros Osam" (42:29), for it is abnormal that they should be called spies. Eliezer requested special Hashgachah - that it should occur today, now, like he says.
2.
Ha'amek Davar: Eliezer did not know whether or not the proper girl is in this area. He requested Hashgachah that if she is, she will come to draw and answer like he said, and if not, no girl will do so.