John Calvin Commentary Genesis 2:4

"These are the generations of the heavens and of the earth when they were created, in the day that Jehovah God made earth and heaven." — Genesis 2:4 (ASV)

These are the generations. Moses's design was to impress deeply upon our minds the origin of the heaven and the earth, which he designates by the word generation.

For there have always been ungrateful and malignant men, who, either by falsely claiming that the world was eternal or by obliterating the memory of creation, would attempt to obscure the glory of God. Thus the devil, by his guile, turns away from God those who are more ingenious and skillful than others, so that each might become a god to himself.

Therefore, it is not a superfluous repetition that instills the necessary fact that the world existed only from the time it was created, because this knowledge directs us to its Architect and Author.

Under the names of heaven and earth, the whole is included by the figure of speech synecdoche. Some Hebrews think that the essential name of God is here finally expressed by Moses, because His majesty shines forth more clearly in the completed world.