Dr. Mustafa Khattab, the Clear Quran - Surah Fussilat, ayah 10

Translation of Surah Fussilat, ayah 10 (41:10)

وَجَعَلَ فِيهَا رَوَٰسِيَ مِن فَوۡقِهَا وَبَٰرَكَ فِيهَا وَقَدَّرَ فِيهَآ أَقۡوَٰتَهَا فِيٓ أَرۡبَعَةِ أَيَّامٖ سَوَآءٗ لِّلسَّآئِلِينَ ١٠
He placed on the earth firm mountains, standing high, showered His blessings upon it, and ordained ˹all˺ its means of sustenance—totaling four Days exactly1—for all who ask.

Foot notes

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These four Days include the first two, so the total period of creation is six heavenly Days.