Moses
Genesis 20:8ESV·traditional attribution

So Abimelech rose early in the morning and called all his servants and told them all these things. And the men were very much afraid.

John Calvin Reformed @genevareformer

8. Therefore Abimelech rose early in the morning . Moses teaches how efficacious the oracle had been. For Abimelech, alarmed at the voice of God, arose in the morning, not only that he himself might quickly obey the command enjoined upon him but that he might also exhort his own people to do the same.

Matthew Henry Presbyterian @wholebiblehenry

Abimelech, being thus warned of God in a dream, takes the warning, and, as one truly afraid of sin and its consequences, he rises early to obey the directions given him. I. He has a caution for his servants, Gen 20:8. Abraham himself could not be more careful than he was to command his household in this matter.

Commenting on Genesis 20:8-13

John Gill Reformed Baptist @doctorgill

Therefore Abimelech rose early in the morning,.... Awaking upon the dream, could sleep no more, his thoughts running upon what had been said to him by the Lord in it: wherefore as soon as it was light he rose from his bed: and called all his servants; his household servants, and particularly his courtiers and counsellors, who had advised him to take Sarah for his...