Philo Judaeus De Cherubim 54

[54] And yet you are not ignorant of the importance of a proper application of ¹ names. For before this time, as you proceed in your history, you show this, when speaking in reference to the same person you say, "And Adam knew Eve his wife, and she conceived and brought forth a son, and she called his name Seth." ² Therefore it was much more necessary in the case of the first-born, who was the beginning of the generation of men from one another, to display the nature of him who was thus conceived and born, in the first place showing that he was a male child, and secondly mentioning his peculiar name, Cain.