ותער כדה…ותרץ…לשאוב ותשאב לכל גמליו (חיי שרה כד:כ)

Since one isn’t allowed to benefit from nissim – miracles, Rivkah didn’t give from the water she gave to Eliezer to the camels to drink.  Why did Eliezer drink from the miracle waters? Since he was thirsty and in danger.  After he drank “ותער כדה ותרץ לשאב ותשאב” – the well water didn’t come up to Rivkah; she had to draw water from the well herself and give it to the camels to drink.