Or HaChaim on Genesis 22:3/אור החיים על בראשית כ״ב:ג׳

1 וישכם אברהם בבוקר. Abraham arose early in the morning. Abraham acted in line with what we know from Leviticus 7,38, that sacrifices may be brought only by day. Our sages also said (Zevachim 98) that one must not bring an offering at night. Abraham therefore set out at an hour that was suitable for bringing an offering. He did not know how far he had to travel and he wanted to have enough time left to offer the sacrifice once he would be at the right place. In view of G'd having addressed Abraham by day, perhaps he should not have waited until the following day; it is possible that he received the instructions in the late afternoon or that Isaac was not at home at the time. By reporting that Abraham rose early, the Torah explains that the day's delay was not due to any negligence on Abraham's part.