Moses
Genesis 16:13ESV·traditional attribution

So she called the name of the LORD who spoke to her, “You are a God of seeing,” for she said, “Truly here I have seen him who looks after me.”

John Calvin Reformed @genevareformer

13. And she called the name of the Lord . Moses, I have no doubt, implies that Hagar, after she was admonished by the angel, changed her mind: and being thus subdued, retook herself to prayer; unless, perhaps, here the confession of the tongue, rather than change of mind, is denoted.

Matthew Henry Presbyterian @wholebiblehenry

We may suppose that the angel having given Hagar that good counsel (Gen 16:9) to return to her mistress she immediately promised to do so, and was setting her face homeward; and then the angel went on to encourage her with an assurance of the mercy God had in store for her and her seed: for God will meet those with mercy that are returning to their duty.

Commenting on Genesis 16:10-14

John Gill Reformed Baptist @doctorgill

And she called the name of the Lord that spake unto her,.... Either she called on the name of the Lord, and prayed unto him, that he would forgive her sin and give her some fresh tokens of his love; and also gave him thanks for his gracious regards unto her, that he should look upon, and look after so mean a creature, and such...