The moment a suspected wife drinks the prepared waters is a profound act of divine judgment and a submission to fate. Far from a mere technical step, the physical act of drinking represents her complete acceptance of God's decree. The water itself serves as a vessel containing the truth of her destiny, actively testing her past [רש"ר הירש].
The exact timing of this event within the ritual is a matter of discussion. The primary approach among commentators is that the events are not recorded in strict chronological order, meaning the woman's meal offering is actually presented before she drinks. In this view, the narrative simply anticipates what will soon occur [רש"י, מזרחי, שפתי חכמים]. Conversely, another perspective takes the sequence literally, maintaining that she drinks before the offering is made [הכתב והקבלה]. A third understanding suggests that the text is not describing the act of drinking at this moment, but rather the priest's purpose: he erases the sacred scroll into the water specifically so she can drink it [בכור שור, ברכת אשר].
On a practical level, the priest must ensure the woman drinks the water without hesitation. He cannot show pity, particularly because God's name has already been erased into the mixture [העמק דבר]. If she attempts to refuse at this late stage, she is forced to drink against her will [בכור שור]. Intriguingly, the act of giving her the water serves as a historical reminder of the Israelites' sin of prostitution at the stream of Shittim, drawing a parallel between her suspected actions and that national failure [קיצור בעל הטורים].
Naturally, the water itself does not possess a strong, physical bitterness. Rather, its status as a curse is revealed through the sudden agony the woman experiences upon drinking it [ביאור שטיינזלץ]. The water transforms into something harsh and harmful for her, as any severe affliction is termed "bitter" [רש"י, גור אריה], with some viewing this specific bitterness as a curse of barrenness [אוהב גר]. It enters her as a piercing truth, yet its destructive power is entirely dependent on her actual guilt, not merely the physical act of swallowing the liquid [רש"ר הירש].
Once consumed, the water spreads throughout her entire body. While the punishment specifically targets the belly and the thigh—since those were the organs involved in the sin and where the affliction begins—the water effectively tests her whole physical being [רש"י]. Furthermore, the repeated mention of the water entering her establishes a principle of equal justice. Just as the water tests the woman and punishes her guilt with physical affliction, it simultaneously tests and inflicts the exact same harm upon the man who sinned with her [תורה תמימה].