Rashi on Yom Echad in Bereishit

(2) בראשית ברא IN THE BEGINNING GOD CREATED — This verse calls aloud for explanation in the manner that our Rabbis explained it: God created the world for the sake of the Torah which is called (Proverbs 8:22) “The beginning (ראשית) of His (God’s) way”, and for the sake of Israel who are called (Jeremiah 2:3) “The beginning (ראשית) of His (God’s) increase’’. If, however, you wish to explain it in its plain sense, explain it thus: At the beginning of the Creation of heaven and earth when the earth was without form and void and there was darkness, God said, “Let there be light”. The text does not intend to point out the order of the acts of Creation — to state that these (heaven and earth) were created first; for if it intended to point this out, it should have written 'בראשונה ברא את השמים וגו “At first God created etc.” And for this reason: Because, wherever the word ראשית occurs in Scripture, it is in the construct state. E. g., (Jeremiah 26:1) “In the beginning of (בראשית) the reign of Jehoiakim”; (Genesis 10:10) “The beginning of (ראשית) his kingdom”; (Deuteronomy 18:4) “The first fruit of (ראשית) thy corn.” Similarly here you must translate בראשית ברא אלהים as though it read בראשית ברוא, at the beginning of God’s creating. A similar grammatical construction (of a noun in construct followed by a verb) is: (Hosea 1:2) תחלת דבר ה' בהושע, which is as much as to say, “At the beginning of God’s speaking through Hosea, the Lord said to Hosea.” Should you, however, insist that it does actually intend to point out that these (heaven and earth) were created first, and that the meaning is, “At the beginning of everything He created these, admitting therefore that the word בראשית is in the construct state and explaining the omission of a word signifying “everything” by saying that you have texts which are elliptical, omitting a word, as for example (Job 3:10) “Because it shut not up the doors of my mother’s womb” where it does not explicitly explain who it was that closed the womb; and (Isaiah 8:4) “He shall take away the spoil of Samaria” without explaining who shall take it away; and (Amos 6:12) “Doth he plough with oxen," and it does not explicitly state, “Doth a man plough with oxen”; (Isaiah 46:10) “Declaring from the beginning the end,” and it does not explicitly state, “Declaring from the beginning of a thing the end of a thing’ — if it is so (that you assert that this verse intends to point out that heaven and earth were created first), you should be astonished at yourself, because as a matter of fact the waters were created before heaven and earth, for, lo, it is written, (v. 2) “The Spirit of God was hovering on the face of the waters,” and Scripture had not yet disclosed when the creation of the waters took place — consequently you must learn from this that the creation of the waters preceded that of the earth. And a further proof that the heavens and earth were not the first thing created is that the heavens were created from fire (אש) and water (מים), from which it follows that fire and water were in existence before the heavens. Therefore you must needs admit that the text teaches nothing about the earlier or later sequence of the acts of Creation.