Midrasch zu Bereschit 24:61

At six hours of the day the servant went forth from Haran, and he took Rebecca and Deborah her nurse and made them ride upon the camels. So that the servant should not be alone with the maiden (Rebecca) by night, the earth was contracted before him, and in three hours the servant came to Hebron at the time of the prayer of the afternoon-evening. And Isaac had gone forth to say the afternoon-evening prayer, as it is said, "And Isaac went forth to meditate in the field towards even" (Gen. 24:63).