בראשית, פרק ז׳, פסוק י״ב

The transition from divine warning to the execution of judgment arrived as the waters began to fall upon the earth. This was not merely a natural weather phenomenon, but a calculated event combining justice and mercy, revealing how God governs His world. The rain started exactly as God had promised and continued relentlessly without a single pause [רד״ק, קאסוטו, ביאור שטיינזלץ]. However, its onset was far from natural. It began with such immediate, overwhelming force that Noah and his family were compelled to enter the ark that very day, completely unable to survive outdoors [מלבי״ם]. The method of destruction was not limited to people drowning in rising groundwater. Instead, the relentless impact of the heavy raindrops physically battered the inhabitants, ultimately causing their flesh to dissolve and be wiped away [העמק דבר].

Despite the severity of the destruction, the event was initially tempered with compassion. At first, the waters fell as ordinary rain. The divine intention was that if the people chose to repent, these waters would serve as a profound blessing to nourish and grow the earth. Only when humanity refused to change did the rain transform into an instrument of ruin [רש״י, מזרחי]. Even though God knew in advance that the people would not abandon their evil ways, He initially brought the rain down gently. This was done to pacify the attribute of divine mercy, which actively sought to defend them. Once mercy witnessed their stubborn rebellion, it finally withdrew its protection [חזקוני]. Physically, the rain also began as normal, cool water rather than boiling water. This careful measure was taken to preserve the seeds and fruits necessary to eventually regrow the world, and only later did the waters become boiling and destructive [משכיל לדוד].

The rain fell for forty days and forty nights. The specific mention of the nights serves to clarify that these were complete, uninterrupted twenty-four-hour periods [משכיל לדוד]. The precise tracking of dates and times during this event is deeply intentional, teaching that certain dates hold lasting spiritual significance for future generations as days of either merit or strict judgment [ברכת אשר על התורה].

Regarding the exact calculation of these forty days, commentators offer differing perspectives based on when the count began. The primary approach among commentators is that the very first day is not included in the forty-day total. Because the rain began in the middle of the day, the preceding night was not part of the storm, meaning the first twenty-four-hour cycle was incomplete. Consequently, the forty full days concluded on the morning of the twenty-eighth of Kislev [רש״י, גור אריה, מזרחי, לבוש האורה]. Conversely, others maintain that the first day is included in the count, suggesting the rain actually began the night before. By this calculation, the first day was a complete cycle, meaning the forty days ended one day earlier, on the twenty-seventh of Kislev [דעת זקנים].