On the very same day refers to the day mentioned in verse 11. In some languages there may be confusion resulting from referring to a particular day here, when the previous line speaks of forty days and forty nights. Therefore it may be necessary to say, for example, “On the day the rain began to fall, Noah and his sons….”

The word order Noah and his sons, Shem and Ham and Japheth, and Noah’s wife and the three wives of his sons is a fixed formula and follows the same order as in 6.18; 7.7. The names of Noah’s sons are added here; and wherever the names of the three sons are used, they occur in the same order, implying that Shem is the oldest and Japheth the youngest. See 6.18 for discussion of three wives of his sons.

Entered the ark: that is, “got into the boat.”

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .