Bede

Noah indeed, when he was five hundred years old, begot Shem, Ham, and Japheth. Therefore, Noah was born in the tenth generation, because he both represented and led the lives of those who are perfect in the observance of the Decalogue. He begot three sons, so that his service to the Lord in the faith of the Holy Trinity and the produce of spiritual virtues would also be signified by the fruit of his physical offspring; although, according to history, it was appropriate for him to have begotten three sons, in whom the seed of the …

Commentary on Genesis (Hexaemeron) ↗