Following the devastation of the global flood, God establishes a permanent rhythm for the natural world. This decree is not merely a guarantee of the earth's survival, but a profound transformation of physical reality and human existence. The assurance that nature will follow a set course for all the days of the earth indicates that the current world has a predetermined lifespan and purpose. The primary approach among commentators is that this promise applies exclusively to the world as it currently exists. In the future, when God forms a new heaven and earth, the laws of nature will undergo yet another transformation [אבן עזרא, רד״ק, רבנו בחיי, חזקוני, ביאור יש״ר, קאסוטו].
To grasp the significance of the newly established seasons, it is essential to understand the climatic and geographic upheaval caused by the flood. Before the deluge, the sun's path aligned perfectly with the equator, blanketing the entire globe in a perpetual, comfortable spring. This ideal environment granted early humans exceptionally long lives, freedom from disease, and abundant agricultural yields that required minimal effort. However, this effortless prosperity and idleness ultimately bred corruption and sin. In the aftermath of the flood, God tilted the earth's axis relative to the sun, introducing extreme seasonal shifts. This drastic climate change was intentionally designed to weaken the human constitution, introduce illness, and significantly shorten lifespans. By forcing humanity to toil endlessly for basic survival, God ensured they would remain occupied, thereby distancing them from arrogance and sin [ספורנו, מלבי״ם, העמק דבר, רש״ר הירש, תולדות יצחק, צאינה וראינה].
The specific division of time established after the flood is explored through several models. The primary approach divides the year into six distinct agricultural and climatic seasons, each lasting two months [רש״י, מזרחי, גור אריה, שפתי חכמים, רש״ר הירש, מחוקקי יהודה]. In this system, the seed season marks the beginning of the autumn rains. Winter represents the middle of autumn, characterized by increasing chill and the sowing of quick-ripening crops. The cold season arrives at the end of the rainy period, bringing weather even harsher and more frigid than winter. Harvest corresponds to the spring. Summer is the period when plants no longer rely on soil moisture, and figs are gathered and dried in the fields. Finally, the heat season marks the end of the sunny months, bringing a sweltering climate far more intense than regular summer. Alternatively, some interpret the annual cycle as split into two primary halves of winter and summer, which are then subdivided into the four familiar seasons [אבן עזרא, רד״ק, ביאור יש״ר]. Others view the listed times as a broader illustration of global seasonal shifts, contrasting periods of rainfall with dry spells, or simply as pairs of natural opposites that will forever govern the earth [שד״ל, קאסוטו].
The divine promise that the natural order will never again cease reveals that these systems completely halted during the flood year. Commentators agree that the celestial bodies did not function normally during the deluge, blurring the boundary between day and night. Some explain that light and darkness were mixed together, or that thick clouds completely obscured the sun, while others suggest that the celestial spheres entirely stopped their rotation. Despite this cosmic standstill, Noah was able to track time inside the ark by utilizing a precious stone that glowed in the darkness, employing timekeeping tools like sundials or water clocks, or carefully observing the daily habits of the animals [רש״י, רד״ק, שפתי חכמים, משכיל לדוד, מיני תרגומא]. The specific assurance that nature will not cease mirrors the story of creation, but with an inverted meaning. Just as God ceased His labor upon completing the world, He now guarantees that the laws of creation themselves will never again cease functioning [קאסוטו].
Beyond its meteorological meaning, the continuous cycle of day and night serves as a moral and legal directive for humanity at large. It establishes a decree that humans must engage in constant labor, as idleness inevitably leads to sin and spiritual ruin. From this principle emerges the rule that a non-Jew is forbidden from establishing a mandatory day of rest akin to the Sabbath. The gift of a weekly day of rest was granted exclusively to Israel, whereas the universal duty of the rest of humanity is the continuous, uninterrupted settlement and development of the world [תורה תמימה, פרדס יוסף, חתם סופר].