Sforno on Genesis 24:63/ספורנו על בראשית כ״ד:ס״ג

1ויצא יצחק לשוח, he had detoured from his regular path to the field in order to pour out his heart to G’d in prayer. He did not want to be interrupted in his devotion by passing travelers whom he would have to greet. This was in spite of the fact that he had already prayed in Beer lachay Ro-i. His prayer had been answered already, in accordance with Daniel 10,12 מן היום אשר נתת את לבך להבין ולהענות...נשמעו דבריך, “for from the first day you set your mind to get understanding, practicing abstinence before your G’d, your prayer was heard and I have come because of your prayer.”

2והנה גמלים באים, when he had gone out to pray, the camels were already headed in his direction. This is what Rivkah referred to when she asked about the man walking “toward us?” (verse 65) This is because when Yitzchok returned from Beer lachay Ro-i to his house he was walking from the north to the south. People coming from Charan (Aram Naharaym) headed for Avraham’s house would be traveling from the east to the west. This is why after having deviated from his route which would have taken him from north to south, and walking in an easterly direction instead, Yitzchok would be walking in the direction from which the camels were approaching, from the land known also as ארץ בני קדם the land belonging to the people of the East. He had reason to believe that Rivkah would come from that direction.