Moses
Genesis 21:8BSB·traditional attribution

So the child grew and was weaned, and Abraham held a great feast on the day Isaac was weaned.

John Calvin Reformed @genevareformer

8. And the child grew, and was weaned . Moses now begins to relate the manner in which Ishmael was rejected from the family of Abraham, in order that Isaac alone might hold the place of the lawful son and heir. It seems, indeed, at first sight, something frivolous, that Sarah, being angry about a mere nothing, should have stirred up strife in the family.

Matthew Henry Presbyterian @wholebiblehenry

Long-looked-for comes at last. The vision concerning the promised seed is for an appointed time, and now, at the end, it speaks, and does not lie; few under the Old Testament were brought into the world with such expectation as Isaac was, not for the sake of any great person eminence at which he was to arrive, but because he was to be, in this...

Commenting on Genesis 21:1-8

John Gill Reformed Baptist @doctorgill

And Sarah saw the son of Hagar the Egyptian,.... That is, Ishmael, who is not expressed by name, but described by being a son of Hagar, a servant of Sarah's, and an Egyptian woman; all which seems to be observed by way of slight, both to Hagar and her son: which she had born unto Abraham; not unto Sarah, as she proposed to herself, when...