Moses
Genesis 12:4ESV·traditional attribution

So Abram went, as the LORD had told him, and Lot went with him. Abram was seventy-five years old when he departed from Haran.

John Calvin Reformed @genevareformer

4. So Abram departed . They who suppose that God was now speaking to Abram in Charran, lay hold of these words in support of their error. But the cavil is easily refuted; for after Moses has mentioned the cause of their departure, namely, that Abram had been constrained by the command of God to leave his native soil, he now returns to the thread of the history.

Matthew Henry Presbyterian @wholebiblehenry

Here is, I. Abraham's removal out of his country, out of Ur first and afterwards out of Haran, in compliance with the call of God: So Abram departed; he was not disobedient to the heavenly vision, but did as he was bidden, not conferring with flesh and blood, Gal 1:15, Gal 1:16.

Commenting on Genesis 12:4-5

John Gill Reformed Baptist @doctorgill

So Abram departed, as the Lord had spoken unto him,.... Or, "when the Lord had spoken to him", as Cocceius renders the words; when he had called him a second time, even when in Haran, immediately after the death of his father Terah; as soon as ever the words were spoken to him before recorded, he immediately prepared and got all things ready for his...