What does Genesis 24:20 mean?
Abraham's servant had asked God that the girl meant to marry Isaac would offer to water his camels without being prompted (Genesis 24:12–14). In the previous verse, Rebekah did exactly that. Now she follows through on her offer to keep bringing water to the trough for the camels until they are finished drinking. She acts quickly and thoroughly.This is likely well beyond what Abraham's servant would have hoped for. Not only has God given the sign that the right girl has been found, she is demonstrating a generous spirit, a sense of hospitality, and a genuine work ethic. The emphasis on Rebekah acting "quickly" seems to confirm that this is unprompted behavior. She's sincerely acting out of good will, not being coerced or manipulated with guilt.
This is a key feature in how Abraham's servant has approached his task to find a wife for Isaac (Genesis 24:3–4). His prayer specifically asked God to send a woman of character. Rebekah's beauty (Genesis 24:16) is certainly a good thing, but it's not the primary trait this man is looking for.