אֱלֹהִ֗ים’ĕ·lō·hîmAnd GodH430 √ ʼĕlôhîym — gods in the ordinary senseNounmasculine plural
God (’ĕlōhîm, H430) — grammatically plural, governing a singular verb; the unbroken subject of every creative act in the chapter.
וַיֹּ֣אמֶרway·yō·mersaidH559 √ ʼâmar — to say (used with great latitude)Conjunctive wawVerbQalConsecutive imperfectthird person masculine singular
The waw-consecutive way·yō·mer (“and-said”) continues the chain of fiats; creation on day four still proceeds by spoken word, not manufacture.
יְהִ֤יyə·hîLet there beH1961 √ hâyâh — to exist, iVerbQalImperfect Jussivethird person masculine singular
yə·hî (“let-there-be”) is singular though its subject mə·’ō·rōṯ is plural. Keil & Delitzsch and the Pulpit Commentary both pause here: the predicate precedes its plural subject (Gesenius §147), so the singular stands — the same construction as v. 3's first yə·hî ’ôr, deliberately echoing day one.
מְאֹרֹת֙mə·’ō·rōṯlightsH3974 √ mâʼôwr — properly, a luminous body or luminary, iNounmasculine plural
mə·’ō·rōṯ (H3974) — the pivot of the verse. A mâ’ôwr is a luminous body, a lamp; the identical word names the lamps of the tabernacle (Exodus 35:14; Leviticus 24:2). Creation's sky is furnished like a sanctuary.
בִּרְקִ֣יעַbir·qî·a‘in the expanseH7549 √ râqîyaʻ — properly, an expanse, iPreposition-bNounmasculine singular construct
bir·qî·a‘ (H7549) — the expanse hammered out on day two (1:6–8). The lights are set in what was already made, not in a fresh creation.
הַשָּׁמַ֔יִםhaš·šā·ma·yimof the skyH8064 √ shâmayim — the sky (as aloftArticleNounmasculine plural
לְהַבְדִּ֕ילlə·haḇ·dîlto distinguishH914 √ bâdal — to divide (in variation senses literally or figuratively, separate, distinguish, differ, select, etcPreposition-lVerbHifilInfinitive construct
lə·haḇ·dîl (H914, Hifil infinitive) — “to cause separation”; the structural hinge linking day four to days one and two.
√ bêyn — between (repeated before each noun, often with other particles)Preposition
bên…ū·ḇên (H996, “between…and-between”) — the doubled preposition the Hebrew repeats before each member of a separation, exactly as in 1:4 and 1:6.
הַיּ֖וֹםhay·yō·wmthe dayH3117 √ yôwm — a day (as the warm hours), whether literal (from sunrise to sunset, or from one sunset to the next), or figurative (a space of time defined by an associated term), (often used adverb)ArticleNounmasculine singular
√ bêyn — between (repeated before each noun, often with other particles)Conjunctive wawPreposition
הַלָּ֑יְלָהhal·lā·yə·lāhthe nightH3915 √ layil — properly, a twist (away of the light), iArticleNounmasculine singular
וְהָי֤וּwə·hā·yūand let them beH1961 √ hâyâh — to exist, iConjunctive wawVerbQalConjunctive perfectthird person common plural
לְאֹתֹת֙lə·’ō·ṯōṯsigns to markH226 √ ʼôwth — a signal (literally or figuratively), as aflag, beacon, monument, omen, prodigy, evidence, etcPreposition-lNouncommon plural
’ō·ṯōṯ (H226, “signs”) — the heavens are appointed witnesses. Keil cites Matthew 2:2 and Luke 21:25; the star over Bethlehem and the signs in sun and moon both draw on this office.
וּלְמ֣וֹעֲדִ֔יםū·lə·mō·w·‘ă·ḏîm[the] seasonsH4150 √ môwʻêd — properly, an appointment, iConjunctive waw, Preposition-lNounmasculine plural
mō·w·‘ă·ḏîm (H4150) — “appointed times”; the LORD ties the festal calendar (cf. Psalm 104:19, “He made the moon for the mo‘edim”) to the motion of the lights.
וּלְיָמִ֖יםū·lə·yā·mîmand daysH3117 √ yôwm — a day (as the warm hours), whether literal (from sunrise to sunset, or from one sunset to the next), or figurative (a space of time defined by an associated term), (often used adverb)Conjunctive waw, Preposition-lNounmasculine plural
וְשָׁנִֽים׃wə·šā·nîmand yearsH8141 √ shâneh — a year (as a revolution of time)Conjunctive wawNounfeminine plural
šā·nîm (H8141, “years”) — the year is the interpretive key to day four as “day” was to day one (so Barnes): the annual circuit of the earth completes what the diurnal circuit began.