Moses
Genesis 15:2ESV·traditional attribution

But Abram said, “O Lord GOD, what will you give me, for I continue childless, and the heir of my house is Eliezer of Damascus?”

John Calvin Reformed @genevareformer

2. And Abram said , Lord God . The Hebrew text has יחוה אדונת ( Adonai Jehovah .) From which appellation it is inferred that some special mark of divine glory was stamped upon the vision; so that Abram, having no doubt respecting its author, confidently broke out in this expression.

Matthew Henry Presbyterian @wholebiblehenry

We have here the assurance given to Abram of a numerous offspring which should descend from him, in which observe, I. Abram's repeated complaint, Gen 15:2, Gen 15:3. This was that which gave occasion to this promise. The great affliction that sat heavy upon Abram was the want of a child; and the complaint of this he here pours out before the Lord, and shows...

Commenting on Genesis 15:2-6

John Gill Reformed Baptist @doctorgill

And Abram said, Lord God, what wilt thou give me, seeing I go childless,.... As if he should say, what signifies what thou givest me of temporal blessings, if thou withholdest from me the blessing of a child; from whom it might be hoped and believed would spring the promised Messiah, in whom all nations of the earth shall be blessed.