Moses
Genesis 4:1ESV·traditional attribution

Now Adam knew Eve his wife, and she conceived and bore Cain, saying, “I have gotten a man with the help of the LORD.”

John Calvin Reformed @genevareformer

1. And Adam knew his wife Eve . Moses now begins to describe the propagation of mankind; in which history it is important to notice that this benediction of God, “Increase and multiply,” was not abolished by sin; and not only so, but that the heart of Adam was divinely confirmed so that he did not shrink with horror from the production of offspring.

Matthew Henry Presbyterian @wholebiblehenry

Adam and Eve had many sons and daughters, Gen 5:4. But Cain and Abel seem to have been the two eldest. Some think they were twins, and, as Esau and Jacob, the elder hated and the younger loved. Though God had cast our first parents out of paradise, he did not write them childless; but, to show that he had other blessings in store for...

Commenting on Genesis 4:1-2

John Gill Reformed Baptist @doctorgill

And Adam knew Eve his wife,.... An euphemism, or modest expression of the act of coition. Jarchi interprets it, "had known", even before he sinned, and was drove out of the garden; and so other Jewish writers, who think he otherwise would not have observed the command, "be fruitful and multiply": but if Adam had begotten children in a state of innocence, they would have...